Merge pull request #424 from mathiasgrimm/typo_fix

typo fix

Author: lucadegasperi

CONTRIBUTING.md

@@ -6,7 +6,7 @@ This is very important so that problems can be issued quicker.
 
 Please ensure that you run `phpunit` from the project root after you've made any changes.
 
-If you've added something new please create a new unit test, if you've changed something please update any unit tests as appropritate.
+If you've added something new please create a new unit test, if you've changed something please update any unit tests as appropriate.
 
 We're trying to ensure there is **100%** test code coverage (including testing PHP errors and exceptions) so please ensure any new/updated tests cover all of your changes.