Fix build.gradle typo from previous backport

build.gradle

@@ -145,7 +145,7 @@ tasks.register("updateCIBwcVersions") {
         new ListExpansion(versions: filterIntermediatePatches(buildParams.bwcVersions.unreleasedIndexCompatible), variable: "BWC_LIST"),
       ],
       [
-        new StepExpansion(templatePath: ".buildkite/pipelines/periodic.bwc.template.yml", versions: filterIntermediatePatches(BuildParams.bwcVersions.allIndexCompatible), variable: "BWC_STEPS"),
+        new StepExpansion(templatePath: ".buildkite/pipelines/periodic.bwc.template.yml", versions: filterIntermediatePatches(buildParams.bwcVersions.allIndexCompatible), variable: "BWC_STEPS"),
       ]
     )