Confirm support for Python 3.13 and drop 3.8

[khaeru]

Python 3.13 will be released 2024-10-01. This PR is to:

• Check/confirm that ixmp is compatible with the new version. This includes the existence of compatible releases of upstream dependencies. If those releases are not immediately available, the PR can aid to monitor and track upstream issues:
  • apache/arrow#43519
  • jpype-project/jpype#1204 and related
  • khaeru/genno#143 and numba further upstream
  • pallets/markupsafe#463
  • ~pretenders/pretenders#153~
• Drop support for Python 3.8, which will reach end-of-life (no more updates, even security updates) "approximately [during, before, or after] October 2024" per PEP 569.
  • [x] Remove any code marked as for Python 3.8 compatibility only. Depending on these changes, part or all of the functionality may remain usable with Python 3.8 if users have extreme need.
  • [x] Make any general clean-ups or improvements possible with features available from Python 3.9.
    • [x] Type hint using generics, e.g. list[str] instead of from typing import List/List[str].
    • [x] Use from collections.abc import Sequence et al instead of deprecated from typing import Sequence.

These changes would then be on main and ready for the next release at any time.

How to review

• Note that the CI checks all pass.

PR checklist

• [x] Continuous integration checks all ✅
• [x] ~Add or expand tests;~ coverage checks both ✅
• ~Add, expand, or update documentation.~ N/A
• [x] Update release notes.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.9%. Comparing base (02c887a) to head (dcf15af). Report is 14 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #544 +/- ## ======================================= - Coverage 98.9% 98.9% -0.1% ======================================= Files 44 44 Lines 4819 4790 -29 ======================================= - Hits 4769 4740 -29 Misses 50 50 ``` | [Files with missing lines](https://app.codecov.io/gh/iiasa/ixmp/pull/544?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa) | Coverage Δ | | |---|---|---| | [ixmp/\_config.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2F_config.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9fY29uZmlnLnB5) | `96.7% <100.0%> (ø)` | | | [ixmp/backend/\_\_init\_\_.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fbackend%2F__init__.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9iYWNrZW5kL19faW5pdF9fLnB5) | `100.0% <100.0%> (ø)` | | | [ixmp/backend/base.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fbackend%2Fbase.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9iYWNrZW5kL2Jhc2UucHk=) | `100.0% <100.0%> (ø)` | | | [ixmp/backend/jdbc.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fbackend%2Fjdbc.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9iYWNrZW5kL2pkYmMucHk=) | `97.2% <100.0%> (ø)` | | | [ixmp/cli.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fcli.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9jbGkucHk=) | `100.0% <100.0%> (ø)` | | | [ixmp/core/platform.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fcore%2Fplatform.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9jb3JlL3BsYXRmb3JtLnB5) | `98.9% <100.0%> (+<0.1%)` | :arrow_up: | | [ixmp/core/scenario.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fcore%2Fscenario.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9jb3JlL3NjZW5hcmlvLnB5) | `99.6% <100.0%> (+<0.1%)` | :arrow_up: | | [ixmp/core/timeseries.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fcore%2Ftimeseries.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9jb3JlL3RpbWVzZXJpZXMucHk=) | `98.6% <100.0%> (+<0.1%)` | :arrow_up: | | [ixmp/model/\_\_init\_\_.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fmodel%2F__init__.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9tb2RlbC9fX2luaXRfXy5weQ==) | `100.0% <100.0%> (ø)` | | | [ixmp/model/base.py](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree&filepath=ixmp%2Fmodel%2Fbase.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9tb2RlbC9iYXNlLnB5) | `100.0% <100.0%> (ø)` | | | ... and [11 more](https://app.codecov.io/gh/iiasa/ixmp/pull/544?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa) | |

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[khaeru]

• Question about maintenance / breaking with bottle v0.13 pretenders/pretenders#153

There doesn't appear to be any upstream response in the last 2+ months. One possibility is we switch away from this to an alternative that seems to be maintained. Alternatives I'm aware of include:

• requests-mock —I have used this myself in other projects, but per jamielennox/requests-mock#262 / pypi/support/issues/4625 it may not be actively maintained.
• pytest-httpserver —I have not used this, but it shows signs of being actively maintained.
• mimicker —Recently updated, but only 35 commits and fewer contributors.
• Others (including DIY examples) mentioned on StackExchange (1, 2).

IIRC pretenders is also a source of flakiness, so a switch could side-step those issues.

[khaeru]

• pytest-httpserver —I have not used this, but it shows signs of being actively maintained.

Okay, that was pretty easily done and the tests where it was used are simplified.

[glatterf42]

Thanks, great news! Especially since the one failed test just failed due to a segfault, so this PR might be complete :)