Bump org.apache.maven.plugins:maven-gpg-plugin from 1.6 to 3.2.4

Bumps [org.apache.maven.plugins:maven-gpg-plugin](https://github.com/apache/maven-gpg-plugin) from 1.6 to 3.2.4.
- [Release notes](https://github.com/apache/maven-gpg-plugin/releases)
- [Commits](apache/maven-gpg-plugin@maven-gpg-plugin-1.6...maven-gpg-plugin-3.2.4)

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

Signed-off-by: dependabot[bot] <[email protected]>

core/pom.xml

@@ -171,7 +171,7 @@
         <maven.resources.plugin.version>3.3.1</maven.resources.plugin.version>
         <maven.release.plugin.version>3.0.1</maven.release.plugin.version>
         <maven.dependency.plugin.version>3.7.1</maven.dependency.plugin.version>
-        <maven.gpg.plugin.version>1.6</maven.gpg.plugin.version>
+        <maven.gpg.plugin.version>3.2.4</maven.gpg.plugin.version>
         <maven.deploy.plugin.version>3.1.2</maven.deploy.plugin.version>
         <maven.source.plugin.version>3.2.1</maven.source.plugin.version>
         <maven.javadoc.plugin.version>3.7.0</maven.javadoc.plugin.version>