Bump org.apache.maven.plugins:maven-gpg-plugin from 3.2.7 to 3.2.8

Bumps [org.apache.maven.plugins:maven-gpg-plugin](https://github.com/apache/maven-gpg-plugin) from 3.2.7 to 3.2.8.
- [Release notes](https://github.com/apache/maven-gpg-plugin/releases)
- [Commits](https://github.com/apache/maven-gpg-plugin/compare/maven-gpg-plugin-3.2.7...maven-gpg-plugin-3.2.8

)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-gpg-plugin
  dependency-version: 3.2.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>