Update to use gitlab-ci-helpers and update deprecated Deployment apiVersion

.gitlab-ci.yml

-image: registry.uninett.no/asm/kubernetes-deploy:v0.13
+include:
+  - project: 'asm/gitlab-ci-helpers'
+    file: '/gitlab-ci-helpers.yml'
 
 variables:
   KUBE_PROD_DOMAIN: dkim.paas2.uninett.no
@@ -14,57 +16,31 @@ stages:
   - production
 
 build:
+  extends: .docker-build
   stage: build
-  script:
-    - build
   only:
     - branches
 
 production:
+  extends: .production
   stage: production
   variables:
     REPLICAS: "2"
   script:
     - deploy dist/kubernetes.yml
-  environment:
-    name: production
-    url: https://$KUBE_PROD_DOMAIN
-  when: manual
-  only:
-    - master
 
 staging:
+  extends: .staging
   stage: staging
   script:
     - deploy dist/kubernetes.yml
-  environment:
-    name: staging
-    url: https://$KUBE_TEST_ID-staging.paas2.uninett.no
-  only:
-    - master
 
 review:
+  extends: .review
   stage: review
   script:
     - deploy dist/kubernetes.yml
-  environment:
-    name: review/$CI_BUILD_REF_NAME
-    url: https://$KUBE_TEST_ID-$CI_ENVIRONMENT_SLUG.paas2.uninett.no
-    on_stop: stop_review
-  only:
-    - branches
-  except:
-    - master
 
 stop_review:
+  extends: .stop_review
   stage: review
-  script:
-    - destroy
-  environment:
-    name: review/$CI_BUILD_REF_NAME
-    action: stop
-  when: manual
-  only:
-    - branches
-  except:
-    - master

dist/kubernetes.yml

-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: $CI_ENVIRONMENT_SLUG
@@ -9,6 +9,9 @@ metadata:
     build_id: "$CI_BUILD_ID"
 spec:
   replicas: $REPLICAS
+  selector:
+    matchLabels:
+      app: $CI_ENVIRONMENT_SLUG
   template:
     metadata:
       labels: