Bump maven-gpg-plugin from 1.4 to 1.6

Bumps maven-gpg-plugin from 1.4 to 1.6.

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

Author: dependabot-preview[bot]

pom.xml

@@ -53,7 +53,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-gpg-plugin</artifactId>
-                <version>1.4</version>
+                <version>1.6</version>
                 <executions>
                     <execution>
                         <id>sign-artifacts</id>