Git Plugin 4.5.1

🐛 Bug Fixes

• JENKINS-64382 - Exclude JGit if submodule extension added (#1017) @MarkEWaite
• JENKINS-56063 - Fix refSpec with expanded variables on first clone (#1013) @Sergio-Mira

📦 Dependency updates

• Bump bom-2.222.x from 18 to 20 (#1015, #1019) @dependabot
• Bump xmlunit-matchers from 2.8.1 to 2.8.2 (#1018) @dependabot
• Bump plugin from 4.13 to 4.15 (#1014, #1020) @dependabot

👻 Maintenance

• Adapt to xstream changes: change readResolve() from private to protected (#1012) @jimklimov

🚦 Tests

• Refine the honor refspec test (#1016) @MarkEWaite