Upgrade mypy

[gruebel]

Pull Request Checklist

Thank you for taking the time to improve Arrow! Before submitting your pull request, please check all appropriate boxes:

• [ ] 🧪 Added tests for changed code.
• [x] 🛠️ All tests pass when run locally (run tox or make test to find out!).
• [x] 🧹 All linting checks pass when run locally (run tox -e lint or make lint to find out!).
• [ ] 📚 Updated documentation for changed code.
• [x] ⏩ Code is up-to-date with the master branch.

If you have any questions about your code changes or any of the points above, please submit your questions along with the pull request and we will try our best to help!

Description of Changes

• Upgrade mypy to the newest version, because it has some nice improvements
• The newest mypy found a typing issue with _ordinal_number for BengaliLocale, which is correct, because it would return None if a negative number is passed in. This behaviour doesn't fit other locales, like OdiaLocale and TamilLocale one. I hope I made the right call here to change the return value to an empty string
• Also added error codes to the type: ignore comments to not automatically ignore other typing issue in the same line
• Also adjusted the mypy config to show the error code, when there is a typing issue and do it pretty 😄 that's how it would look like

  arrow/arrow.py:173: error: "tzinfo" has no attribute "zone"  [attr-defined]
              tzinfo = parser.TzinfoParser.parse(tzinfo.zone)
                                                 ^

[codecov[bot]]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage :thumbsup:

Coverage data is based on head (f5e0476) compared to base (8cac5fa). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1129 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 9 9 Lines 2318 2319 +1 Branches 492 492 ========================================= + Hits 2318 2319 +1 ``` | [Impacted Files](https://codecov.io/gh/arrow-py/arrow/pull/1129?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py) | Coverage Δ | | |---|---|---| | [arrow/arrow.py](https://codecov.io/gh/arrow-py/arrow/pull/1129/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py#diff-YXJyb3cvYXJyb3cucHk=) | `100.00% <100.00%> (ø)` | | | [arrow/locales.py](https://codecov.io/gh/arrow-py/arrow/pull/1129/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py#diff-YXJyb3cvbG9jYWxlcy5weQ==) | `100.00% <100.00%> (ø)` | | | [arrow/parser.py](https://codecov.io/gh/arrow-py/arrow/pull/1129/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py#diff-YXJyb3cvcGFyc2VyLnB5) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py)

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[krisfremen]

Hehe, yeah, but more than just mypy here. I will take a deeper look tonight.

[gruebel]

@krisfremen yeah sorry 😅 I started a small and then more and more small changes were added. I can also split the PR, if you feel more comfortable with it.

[krisfremen]

@gruebel yeah, i don't mind the PR as is, but just for clarity, but let's do the mypy stuff in this PR and split out the version bumps for the rest of the precommit and the GitHub actions in another PR.

Otherwise looks great! Thanks for contributing!

[gruebel]

@krisfremen thanks 🍻

As suggested I split this PR into 2.