Bump org.apache.maven.plugins:maven-gpg-plugin from 3.2.4 to 3.2.8

Bumps [org.apache.maven.plugins:maven-gpg-plugin](https://github.com/apache/maven-gpg-plugin) from 3.2.4 to 3.2.8.
- [Release notes](https://github.com/apache/maven-gpg-plugin/releases)
- [Commits](apache/maven-gpg-plugin@maven-gpg-plugin-3.2.4...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>

Author: dependabot[bot]

pom.xml

@@ -57,7 +57,7 @@
     <maven-surefire-plugin.version>3.5.4</maven-surefire-plugin.version>
     <maven-javadoc-plugin.version>3.8.0</maven-javadoc-plugin.version>
     <maven-source-plugin.version>3.3.1</maven-source-plugin.version>
-    <maven-gpg-plugin.version>3.2.4</maven-gpg-plugin.version>
+    <maven-gpg-plugin.version>3.2.8</maven-gpg-plugin.version>
     <maven-jar-plugin.version>3.5.0</maven-jar-plugin.version>
     <maven-deploy-plugin.version>3.1.2</maven-deploy-plugin.version>
     <maven-clean-plugin.version>3.4.0</maven-clean-plugin.version>