Add version to the images again

.gitlab-ci.yml

+variables:
+  VERSION: ${CI_COMMIT_TAG}
+
 before_script:
   - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
 
 #php-7.0:
 #  stage: build
 #  script:
-#    - docker build --pull --build-arg ALPINE_VERSION=3.5 --build-arg PHP_VERSION=7.0 -t $CI_REGISTRY_IMAGE:php-7.0 .
+#    - docker build --pull --build-arg ALPINE_VERSION=3.5 --build-arg PHP_VERSION=7.0 --build-arg VERSION=${VERSION} -t $CI_REGISTRY_IMAGE:php-7.0 .
 #    - docker push $CI_REGISTRY_IMAGE:php-7.0
 #  only:
 #    - master
@@ -12,7 +15,7 @@ before_script:
 #php-7.1:
 #  stage: build
 #  script:
-#    - docker build --pull --build-arg ALPINE_VERSION=3.7 --build-arg PHP_VERSION=7.1 -t $CI_REGISTRY_IMAGE:php-7.1 .
+#    - docker build --pull --build-arg ALPINE_VERSION=3.7 --build-arg PHP_VERSION=7.1 --build-arg VERSION=${VERSION} -t $CI_REGISTRY_IMAGE:php-7.1 .
 #    - docker push $CI_REGISTRY_IMAGE:php-7.1
 #  only:
 #    - master
@@ -20,7 +23,7 @@ before_script:
 php-7.2:
   stage: build
   script:
-    - docker build --pull --build-arg ALPINE_VERSION=3.8 --build-arg PHP_VERSION=7.2 -t $CI_REGISTRY_IMAGE:php-7.2 .
+    - docker build --pull --build-arg ALPINE_VERSION=3.8 --build-arg PHP_VERSION=7.2 --build-arg VERSION=${VERSION} -t $CI_REGISTRY_IMAGE:php-7.2 .
     - docker push $CI_REGISTRY_IMAGE:php-7.2
   only:
     - master
@@ -28,7 +31,7 @@ php-7.2:
 php-7.3:
   stage: build
   script:
-    - docker build --pull --build-arg ALPINE_VERSION=3.11 --build-arg PHP_VERSION=7.3 -t $CI_REGISTRY_IMAGE:php-7.3 .
+    - docker build --pull --build-arg ALPINE_VERSION=3.11 --build-arg PHP_VERSION=7.3 --build-arg VERSION=${VERSION} -t $CI_REGISTRY_IMAGE:php-7.3 .
     - docker push $CI_REGISTRY_IMAGE:php-7.3
   only:
     - master

Dockerfile

@@ -4,6 +4,7 @@ FROM alpine:${ALPINE_VERSION}
 
 LABEL com.example.vendor="LakeDrops" \
       maintainer="juergen.haas@lakedrops.com" \
+      version="${VERSION}" \
       description="An image for GitLab runner to build and test Drupal projects."
 
 ARG ALPINE_VERSION