Update JGit version used to detect API changes to 4.6.0

We detect API changes during the Maven build using japicmp. Update the
reference version to the latest minor version 4.6.0.

Change-Id: I70f65f4a0680671612f21ee1afac7f7ef0152cbb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

pom.xml

@@ -191,7 +191,7 @@
     <maven.build.timestamp.format>yyyyMMddHHmm</maven.build.timestamp.format>
     <bundle-manifest>${project.build.directory}/META-INF/MANIFEST.MF</bundle-manifest>
 
-    <jgit-last-release-version>4.2.0.201601211800-r</jgit-last-release-version>
+    <jgit-last-release-version>4.6.0.201612231935-r</jgit-last-release-version>
     <jsch-version>0.1.54</jsch-version>
     <javaewah-version>1.1.6</javaewah-version>
     <junit-version>4.12</junit-version>