ci: fix GitHub action syntax .github/workflows/run_relup_tests.yaml

.github/workflows/run_relup_tests.yaml

@@ -58,7 +58,7 @@ jobs:
   relup_test_run:
     needs:
       - relup_test_plan
-    if: needs.relup_test_plan.outputs.OLD_VERSIONS != "[]"
+    if: needs.relup_test_plan.outputs.OLD_VERSIONS != '[]'
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false