SET-807 Strip leading / trailing whitespaces from provided github use…

…rname

...during new user registration

src/main/java/org/jboss/set/mjolnir/server/service/GitHubServiceImpl.java

@@ -86,6 +86,7 @@ public EntityUpdateResult<RegisteredUser> modifyGitHubName(String newGithubName)
         if (StringUtils.isBlank(newGithubName)) {
             return EntityUpdateResult.validationFailure("Github name must be non blank.");
         }
+        newGithubName = newGithubName.strip();
 
         try {
             // reload authenticated user form database