Bump maven-gpg-plugin from 1.6 to 3.0.1

Bumps [maven-gpg-plugin](https://github.com/apache/maven-gpg-plugin) from 1.6 to 3.0.1.
- [Release notes](https://github.com/apache/maven-gpg-plugin/releases)
- [Commits](https://github.com/apache/maven-gpg-plugin/compare/maven-gpg-plugin-1.6...maven-gpg-plugin-3.0.1)

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

pom.xml

@@ -38,7 +38,7 @@
         <java.version>1.8</java.version>
         <maven-javadoc-plugin.version>3.3.0</maven-javadoc-plugin.version>
         <maven-source-plugin.version>3.2.1</maven-source-plugin.version>
-        <maven-gpg-plugin.version>1.6</maven-gpg-plugin.version>
+        <maven-gpg-plugin.version>3.0.1</maven-gpg-plugin.version>
         <maven-deploy-plugin.version>3.0.0-M1</maven-deploy-plugin.version>
         <nexus-staging-maven-plugin.version>1.6.8</nexus-staging-maven-plugin.version>
     </properties>