Add end-of-line character

.github/mergeable.yml

@@ -15,4 +15,4 @@ mergeable:
                 message: 'Please add a language ("lang/*") label'
           - must_include:
               regex: 'release notes: no'
-              message: 'Please add the label "release notes: no"'
+              message: 'Please add the label "release notes: no"'