add ability to add gnupg public keys in building git packages

[Dylan1496]

Useful for certain packages that have publicpgpkey arrays in their PKGBUILD file. Enables one to avoid having to quit out of the pikaur process to add the key using gpg.

This requires the python-gnupg package - the PKGBUILD file has been updated to reflect this.

[actionless]

thanks!

This requires the python-gnupg package

please make it an optional dependency instead (and optional import, right before your second prompt, if can't import - just print that opt dep missing -> re-show main recovery prompt again)

and add to makedeps here: https://github.com/actionless/pikaur/blob/master/pikaur_static/PKGBUILD

and also resolve CI linting errors