[py] Make get_screenshot_as_file() work with pathlib.Paths

[NickCrews]

It currently expects a string (or something with .lower()), but accepting Paths seems quite reasonable.

I supposed if we wanted to be more strict and ensure the passed thing was path-like, we could instead do str(Path(filename)).lower()

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[CLAassistant]

All committers have signed the CLA.

[symonk]

Thanks @NickCrews, it's on my radar to convert everything to support pathlib

[NickCrews]

Just signed the CLA.

It looks to me like the CI failure is unrelated?

[symonk]

Thanks @NickCrews yep it is, some issues ongoing atm - Thanks for the contribution, much appreciated