type checking CI is failing

[keewis]

The most recent runs of the type checking CI have started to fail with a segfault:

/home/runner/work/_temp/dac0c060-b19a-435a-8063-bbc5b8ffbf24.sh: line 1:  2945 Segmentation fault      (core dumped) python -m mypy --install-types --non-interactive --cobertura-xml-report mypy_report

This seems to be due to the release of mypy=0.990.

#7269 pinned mypy to mypy<0.990, which should be undone once we figured out how to fix that (most likely by waiting on the next release), and any complaints the new version has (see this workflow run).

[headtr1ck]

Locally (Windows) it works for me.

Only lots of new errors, most importantly the change of mypy to no_implicit_optional=True.
Guess we can just fix this in a PR, I like the explicit defaults anyway better.

[keewis]

should this have been closed by #7283?

[headtr1ck]

should this have been closed by #7283?

Too long ago...
I assume I had a reason why I didn't close this issue?