setuptools_scm: fix requirements. (#9330)

Should fix buildmaster issues for:
- importlib_metadata
- importlib_resourses
- iniconfig
- pyparsing

python3.8: bulk removal of now obsolete "_python38" packages. (#9328)

* python3.8: bulk removal of now obsolete "_python38" packages.

Done via scripting. No functional change intended or expected.

Some manual tweaks will follow.

* python3.8: further manual tweaks after bulk-3.8-removal.

Unlike the previous commit with automated changes,
I've tested builds for *these* recipes in beta4 64 bits.

setuptools(_scm), bump version (#8758)