[core] update scm url

Forgot to update the scm url in the pom when the core-1.5.x branch was created.  Now the url is correct again.

pom.xml

@@ -216,7 +216,7 @@
 	</mailingLists>
 
 	<scm>
-		<url>https://github.com/wicketstuff/core</url>
+		<url>https://github.com/wicketstuff/core/tree/core-1.5.x</url>
 		<connection>scm:git:ssh://git@github.com:wicketstuff/core.git</connection>
 	</scm>