Update dependency org.apache.maven.plugins:maven-gpg-plugin to v3.2.8

Author: renovate[bot]

pom.xml

@@ -129,7 +129,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-gpg-plugin</artifactId>
-                <version>3.2.7</version>
+                <version>3.2.8</version>
                 <executions>
                     <execution>
                         <id>sign-artifacts</id>