There's a version of bash that can't ${foo,, ?

Author: jcflack

.github/workflows/ci-lazypg.yml

@@ -55,7 +55,7 @@ jobs:
           echo >>"$GITHUB_ENV" "JAVA_HOME=${!candidate}"
           echo >>"$GITHUB_OUTPUT" java_found=true
         elif
-          candidate="JAVA_HOME_${JAVAVER}_${RUNNER_ARCH,,[A-Z]}"
+          candidate="JAVA_HOME_${JAVAVER}_$(tr A-Z a-z <<<${RUNNER_ARCH})"
           echo -ne 'no\n'"Environment contains $candidate? "
           [[ -n ${!candidate+set} ]]
         then