ReceivePack: Add missing @SInCE tag for new API method

Change-Id: I3251799d8361666e000ea089798f8d8575b70cd7

Author: msohn

org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java

@@ -1107,6 +1107,7 @@ public long getPackSize() {
 	 * @return if the client is a shallow repository, the list of edge commits
 	 *         that define the client's shallow boundary. Empty set if the
 	 *         client is earlier than Git 1.9, or is a full clone.
+	 * @since 7.7
 	 */
 	protected Set<ObjectId> getClientShallowCommits() {
 		return clientShallowCommits;