DevOps: Update the `mypy` pre-commit dependency

[sphuber]

The requirement is updated to mypy==0.930. This allows us to move the configuration from tox.ini to the pyproject.toml file. The config in .pre-commit-config.yaml is also corrected as the include path did not properly include the src starting folder.

The remaining configuration for tox.ini is also moved to the pyproject.toml and deleted.

[codecov[bot]]

Codecov Report

Base: 90.72% // Head: 90.72% // No change to project coverage :thumbsup:

Coverage data is based on head (778d6ba) compared to base (fdf4c63). Patch coverage: 71.43% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #246 +/- ## ======================================= Coverage 90.72% 90.72% ======================================= Files 21 21 Lines 2961 2961 ======================================= Hits 2686 2686 Misses 275 275 ``` | [Impacted Files](https://codecov.io/gh/aiidateam/plumpy/pull/246?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam) | Coverage Δ | | |---|---|---| | [src/plumpy/utils.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS91dGlscy5weQ==) | `81.51% <0.00%> (ø)` | | | [src/plumpy/persistence.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9wZXJzaXN0ZW5jZS5weQ==) | `93.93% <50.00%> (ø)` | | | [src/plumpy/base/state\_machine.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9iYXNlL3N0YXRlX21hY2hpbmUucHk=) | `86.13% <80.00%> (ø)` | | | [src/plumpy/\_\_init\_\_.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9fX2luaXRfXy5weQ==) | `100.00% <100.00%> (ø)` | | | [src/plumpy/events.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9ldmVudHMucHk=) | `88.71% <100.00%> (ø)` | | | [src/plumpy/mixins.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9taXhpbnMucHk=) | `90.91% <100.00%> (ø)` | | | [src/plumpy/processes.py](https://codecov.io/gh/aiidateam/plumpy/pull/246/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#diff-c3JjL3BsdW1weS9wcm9jZXNzZXMucHk=) | `92.41% <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=aiidateam). 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=aiidateam)

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