changed empty string

Author: denise-khuu

.github/workflows/checkCourseName.yml

@@ -32,7 +32,7 @@ jobs:
               fi
             fi
           done
-          if [[ message != "" ]]; then
+          if [[ ! -z "$message" ]]; then
             message="${message} The name of your course is already used on a playbook. Please change the name. "
           fi
           echo "::set-output name=message::$message"