Issue #3194401: Switch to CircleCI as the default automated testing platform

.circleci/config.yml

@@ -7,7 +7,7 @@ aliases:
 jobs:
   build:
     docker:
-      - image: circleci/php:7.3-apache-stretch-node-browsers
+      - image: circleci/php:7.3-apache-node-browsers
         auth:
           username: mydockerhub-user
           password: $DOCKERHUB_PASSWORD