Adjust expected exceptions in option merging tests for PyPy3

[mgorny]

PyPy3 raises ValueError rather than TypeError when trying to combine a dict and a str in dict unpacking. Update the test expectations appropriately.

Fixes #580

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I've also fixed CI testing for Python 3.10 (no tox targets were run) and added 3.11 and all PyPy3 versions. They seem to all pass on my fork, except for codecov uploads (obviously).

[mgorny]

I've removed pypy-3.7 to avoid windows failures. AFAIR it's going to be discontinued in the next release anyway.

[auvipy]

wise decision

[mgorny]

Thanks!