[Misc] Bulletproofing source link resolution

(cherry picked from commit 250dfb8)

Author: tmortagne

pom.xml

@@ -36,6 +36,7 @@
   <packaging>pom</packaging>
   <description>XWiki Rendering - Parent POM</description>
   <scm>
+    <url>https://github.com/${xwiki.github.owner}/${xwiki.github.repository}/tree/master/</url>
     <tag>HEAD</tag>
   </scm>
   <issueManagement>