Update CONTRIBUTING.md

Author: Till Brehm

CONTRIBUTING.md

@@ -9,7 +9,7 @@ Please do not refactor existing code and do not change the signature or the beha
 * Before opening a new issue, use the search function to check if there isn't a bug report / feature request already.
 * If you are reporting a bug, please share your OS and PHP (CLI) version.
 * If you want to report several bugs or request several features, open a separate issue for each one of them.
-* Do note re-open issues that were closed by the core dev team unles something new and important that is not mentioned in the original issue needs to be added. Permamnently re-opening issues that we commented on and closed will get your account banned. You may add comments to issues without re-opening them though.
+* Do note re-open issues that were closed by the core dev team unless something new and important that is not mentioned in the original issue needs to be added. Permanently re-opening issues that we commented on and closed will get your account banned. You may add comments to issues without re-opening them though.
 
 # Branches
 * If you are a new user, please send an email to: dev [at] ispconfig [dot] org to receive rights to fork the project.