Feature request: support short package files identifiers as arguments for: pypi-attestations verify pypi

[Lucas-C]

Following the introduction of pypi-attestations verify pypi in #82, I would like to suggest to support "short package files identifiers" to be accepted instead of long pythonhosted.org URLs, like this:

pypi-attestations verify pypi fpdf2/#fpdf2-2.8.2.tar.gz

fpdf2/#fpdf2-2.8.2.tar.gz would be resolved to pypi.org/project/fpdf2#fpdf2-2.8.2.tar.gz and then to the corresponding pythonhosted.org URL.

What do you think about this improvement in terms of ergonomy/usage?