CI/CD: add alternative version tag

.gitlab-ci.yml

@@ -35,19 +35,27 @@ build-docker-image:       # This job runs in the build stage, which runs first.
         -u "$CI_REGISTRY_USER"
         -p "$CI_REGISTRY_PASSWORD"
         $CI_REGISTRY
+    - export VERSION="$(echo
+        "${CI_COMMIT_BRANCH}_$(date +%Y%m%dT%H%M%S)_${CI_COMMIT_SHA:0:8}"
+        |sed 's,/,--,g')"
   # Default branch leaves tag empty (= latest tag)
   # All other branches are tagged with the escaped branch name (commit ref slug)
   script:
     - |
-      if [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
+      if [ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]; then
         tag=""
         echo "Running on default branch '$CI_DEFAULT_BRANCH': tag = 'latest'"
       else
         tag=":$CI_COMMIT_REF_SLUG"
         echo "Running on branch '$CI_COMMIT_BRANCH': tag = $tag"
       fi
-    - docker build --pull -t "$CI_REGISTRY_IMAGE${tag}" .
+    - docker build
+        --pull
+        --file Docker
+        --tag "$CI_REGISTRY_IMAGE${tag}" .
+        --tag "$CI_REGISTRY_IMAGE:$VERSION" .
     - docker push "$CI_REGISTRY_IMAGE${tag}"
+    - docker push "$CI_REGISTRY_IMAGE:$VERSION"
   # Run this job in a branch where a Dockerfile exists
   rules:
     - if: $CI_COMMIT_BRANCH