Fix typo in description

Author: timoxd7

README.md

@@ -40,7 +40,7 @@ github:
     # (default: https://api.github.com)
     url: https://github.mydomain.com
     # (optional) Exclude this list of repos
-    excluded:
+    exclude:
       - my-namespace/excluded-repository-name
 # The gitlab section contains backup jobs for
 # GitLab.com and GitLab on premise
@@ -68,7 +68,7 @@ gitlab:
     # (default: https://gitlab.com/)
     url: https://gitlab.mydomain.com
     # (optional) Exclude this list of repos
-    excluded:
+    exclude:
       - my-namespace/excluded-repository-name
 ```