[PETOSS-829] Use correct option key

Author: the-chris-mitchell

.github/workflows/pr-validation.yml

@@ -121,7 +121,7 @@ jobs:
       - name: MegaLinter
         uses: oxsecurity/megalinter@v9
         env:
-          ENABLED_LINTERS: YAML_YAMLLINT
+          ENABLE_LINTERS: YAML_YAMLLINT
           YAML_YAMLLINT_CONFIG_FILE: .yamllint.yml
           APPLY_FIXES: none
           LOG_LEVEL: INFO