Suppress "unresolved Maven property" warning in IntelliJ for 'maven.gpg

.skip'

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

pom.xml

@@ -365,6 +365,7 @@
 							</goals>
 							<configuration>
 								<!-- Only sign artifacts which are also meant to be deployed -->
+								<!--suppress UnresolvedMavenProperty -->
 								<skip>${maven.gpg.skip}</skip>
 							</configuration>
 						</execution>