Update dependency org.apache.maven.plugins:maven-gpg-plugin to v1.6

Author: renovate[bot]

pom.xml

@@ -134,7 +134,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-gpg-plugin</artifactId>
-                <version>1.5</version>
+                <version>1.6</version>
                 <configuration>
                     <keyname>top.mryan2005.maven</keyname>
                 </configuration>