Add a missing since tag

Otherwise you get errors if you want to edit JGit in Eclipse

Change-Id: I840d4388f159e2db27845a17030b511fc5708f43

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevWalk.java

@@ -1314,6 +1314,7 @@ public class RevWalk implements Iterable<RevCommit> {
 	 * @param ids
 	 *            commits that should be treated as shallow commits, in addition
 	 *            to any commits already known to be shallow by the repository.
+	 * @since 3.3
 	 */
 	public void assumeShallow(Collection<? extends ObjectId> ids) {
 		for (ObjectId id : ids)