Add extra logging to NotUpdatedPRFilter when PR is not updated (#299)

* Add extra logging to NotUpdatedPRFilter when PR is not updated

Currently, the `apply` method only logs to the TaskListener. With this change, it will also log to the
local `Logger`, so we can find the output in the main Jenkins logs. This will help with debugging issues
related to NotUpdatedPRFilter.

* Remove trailing spaces

* Change tabs to spaces

* Change log level of `apply` logging from info to debug

Author: pieterpaladin

github-pullrequest-plugin/src/main/java/org/jenkinsci/plugins/github/pullrequest/trigger/check/NotUpdatedPRFilter.java

@@ -38,7 +38,9 @@ public boolean apply(GHPullRequest remotePR) {
         @CheckForNull GitHubPRPullRequest localPR = localRepo.getPulls().get(remotePR.getNumber());
 
         if (!isUpdated(remotePR, localPR)) { // light check
-            logger.getLogger().println(String.format("PR [#%s %s] not changed", remotePR.getNumber(), remotePR.getTitle()));
+            String logMessage = String.format("PR [#%s %s] not changed", remotePR.getNumber(), remotePR.getTitle());
+            logger.getLogger().println(logMessage);
+            LOGGER.debug(logMessage);
             return false;
         }
         return true;