Window: get python 3.10 tests running in CI

[goodboy]

There's some weird ass bug with pyreadline as per #259 which tracks down to something inside pytest (https://github.com/pytest-dev/pytest/issues/8733, which led to https://github.com/pytest-dev/pytest/issues/8847).

We likely need to re-factor the whole actions matrix anyway to simplify some things:

• don't duplicate job defs for msgspec and instead use a parameter
• make it easier to control filtering for diff OSs whether that's through if controls or wtv..

Relevant GH actions resources,

• https://stackoverflow.com/questions/65384420/how-to-make-a-github-action-matrix-element-conditional
• https://docs.github.com/en/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
• https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions#jobsjob_idstrategymatrix
• https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions#jobsjob_idif
• https://docs.github.com/en/actions/learn-github-actions/expressions

[goodboy]

think this is done now yah?