Fix typo in CONTRIBUTING.md

Signed-off-by: Jan Kiszka <[email protected]>

CONTRIBUTING.md

@@ -11,7 +11,7 @@ steps.
 
 ## Contribution Checklist
 
-- use git to manage your changes [*recomended*]
+- use git to manage your changes [*recommended*]
 - follow Python coding style outlined in pep8 [**required**]
 - add signed-off to all patches [**required**]
     - to certify the "Developer's Certificate of Origin", see below