feat(verification): Add PublicKeyIdentifier hash matching and old-sty…

[SequeI]

Summary

• Fixed some tests for linter
• Added more robust parsing for the bundle which was erroring out (Working off of main/sigstore-python)
• Switched PublicKey to PublicKeyIdentifier
• Added error handling + warning to old style verification material (tested verifying older signatures)
• Verification material now checks with user provided public key in verifier
• Updated changelog

Resolves #491

Checklist

• All commits are signed-off, using DCO
• All new code has docstrings and type annotations
• All new code is covered by tests. Aim for at least 90% coverage. CI is configured to highlight lines not covered by tests.
• Public facing changes are paired with documentation changes
• Release note has been added to CHANGELOG.md if needed

[mihaimaruseac]

Thank you! I'll run some testing and then press the merge button soon.