Adding new enums for verification reasons using X.509 certificate sig…

[AstroTlaloc]

Description

Fixes: #1714

GHVerification$Reason needs to be updated with new unverified values for signatures using X.509 certificates as signing key. Github documentation: https://docs.github.com/en/graphql/reference/enums#gitsignaturestate

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[codecov]

Codecov Report

All modified lines are covered by tests ✅

Files	Coverage Δ
...c/main/java/org/kohsuke/github/GHVerification.java	100.00% <100.00%> (ø)

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[AstroTlaloc]

@bitwiseman can you help me out reviewing this PR?