Revert platformdirs on MacOS and Windows

[Gitznik]

• I have added a news fragment under changelog.d/ (if the patch affects the end users)

Summary of changes

On MacOS and Windows, we now use the old paths again, while using the post 1.2.0 paths as fallback.
On Linux - nothing changed.

Resolves #1257

Test plan

Tested by running

Existing test suite

[chrysle]

By the way, should we have pipx automatically remove the old location if the new one exists and is populated?

[jaraco]

IMHO - if platformdirs isn't providing any value on Windows or Mac, it should probably be removed and pipx should fallback to a consistent behavior across platforms.

[Gitznik]

IMHO - if platformdirs isn't providing any value on Windows or Mac, it should probably be removed and pipx should fallback to a consistent behavior across platforms.

The benefit is specifically on linux, adhering to the xdg spec. IMO that's a good reason to keep it. we need to keep the package anyways to be backwards compatible with anyone that used the default location since 1.2

By the way, should we have pipx automatically remove the old location if the new one exists and is populated?

I don't think I'm fond of automatically removing it, but maybe we can print a hint that it can safely be deleted by the user?

[chrysle]

The benefit is specifically on linux, adhering to the xdg spec. IMO that's a good reason to keep it.

As especially downstream packagers are really pleased if it is being followed (see e.g. Debian).

I don't think I'm fond of automatically removing it, but maybe we can print a hint that it can safely be deleted by the user?

Let's do this at info level.