pom.xml: Update plugin parent to 4.7

This is just a routine update.
No major imrovements are in the new version.

Signed-off-by: Bastian Germann <bage@linutronix.de>

Author: Bastian Germann

pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
-        <version>4.6</version>
+        <version>4.7</version>
         <relativePath />
     </parent>
     <groupId>org.jenkins-ci.plugins</groupId>