Make Go and Ruby versions more readable in CI

.gitlab-ci.yml

@@ -10,9 +10,9 @@ include:
 variables:
   DOCKER_VERSION: "20.10.15"
   BUNDLE_FROZEN: "true"
-  GO_VERSION: "1.18"
+  GO_VERSION: "golang-1.18"
   DEBIAN_VERSION: "bullseye"
-  RUBY_VERSION: "2.7"
+  RUBY_VERSION: "ruby-2.7"
 
 workflow:
   rules: &workflow_rules
@@ -24,7 +24,7 @@ workflow:
     - if: '$CI_COMMIT_TAG'
 
 default:
-  image: registry.gitlab.com/gitlab-org/gitlab-build-images/debian-${DEBIAN_VERSION}-ruby-${RUBY_VERSION}-golang-${GO_VERSION}:git-2.36
+  image: registry.gitlab.com/gitlab-org/gitlab-build-images/debian-${DEBIAN_VERSION}-${RUBY_VERSION}-${GO_VERSION}:git-2.36
   tags:
     - gitlab-org
 
@@ -56,8 +56,8 @@ tests:
   extends: .test
   parallel:
     matrix:
-      - GO_VERSION: ["1.17", "1.18", "1.19"]
-      - RUBY_VERSION: ["2.7", "3.0"]
+      - GO_VERSION: ["golang-1.17", "golang-1.18", "golang-1.19"]
+      - RUBY_VERSION: ["ruby-2.7", "ruby-3.0"]
   script:
     - make verify test
   after_script: