[3006.x] Removing support for Python 3.7 and 3.8 from pre-commit

[dmurphy18]

What does this PR do?

Removes support for Python 3.7 and 3.8 from pre-commit and support in generated requirements for those versions of Python
Leaving support for Python 3.9 as this is required at the moment in order to build, that is, build tools/scripts/actions are currently making use of system python, for example: Rocky Linux 9 is using Python 3.9.

What issues does this PR fix or reference?

Fixes #67729

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

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Yes

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[dmurphy18]

@twangboy Allows us to update the requirements dependencies since we don't have to maintain older versions of those dependencies, for example: support Python 3.7 which will have been dropped by a number of dependencies already, but we have to use older versions of those dependencies which are compatible with Python 3.7..
Reduces the footprint that we have to deal with.

[dmurphy18]

Don't know which button I hit to close this prematurely, reopened it

[dwoz]

I don't know what the rush is here. I would say we drop support for these older ones once they stop compiling properly. Though we don't support older versions of Python, people still use Salt on older platforms. The current requirements files we compile aren't really a huge overhead and don't hurt us, but would cause a lot of inconvenience to some of our users if they're removed.

I am not opposed to this but I also don't see a need to rush it.