Once MSYS2 repository updates past Python 3.12, this commit can be
reverted.
Explanation:
CPython 3.12 can't pass sys_settrace_features test (see parent commit for
explanation). MSYS2 mingw-w64-ARCH-python package is currently 3.12.7.
MSYS2 doesn't recommend installing old packages from their archive (due to
library dependencies), so switch to the GitHub CI setup-python action for
now.
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
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