Wrap env var around curl braces

Author: MarcialRosales

.github/workflows/test-authnz.yaml

@@ -77,8 +77,8 @@ jobs:
         IMAGE_TAG=$(find PACKAGES/rabbitmq-server-generic-unix-*.tar.xz | awk -F 'PACKAGES/rabbitmq-server-generic-unix-|.tar.xz' '{print $2}')
         CONF_DIR_PREFIX="$(mktemp -d)" RABBITMQ_DOCKER_IMAGE=pivotalrabbitmq/rabbitmq:$IMAGE_TAG \
          ${SELENIUM_DIR}/run-suites.sh full-suite-authnz-messaging 
-        echo "Producing env var SELENIUM_ARTIFACTS with value $CONF_DIR_PREFIX"
-        echo "SELENIUM_ARTIFACTS=$CONF_DIR_PREFIX" >> $GITHUB_ENV
+        echo "Producing env var SELENIUM_ARTIFACTS with value ${CONF_DIR_PREFIX}"
+        echo "SELENIUM_ARTIFACTS=${CONF_DIR_PREFIX}" >> $GITHUB_ENV
         
     - name: Upload Test Artifacts
       if: always()