[maven-release-plugin] rollback the release of 6.1.3

Author: line-o

pom.xml

@@ -378,7 +378,6 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-gpg-plugin</artifactId>
         <configuration>
-          <skip>true</skip>
           <useAgent>true</useAgent>
         </configuration>
       </plugin>