Pin deployment image to build number tag instead of restarting latest

Images are now tagged with both :latest and :${DRONE_BUILD_NUMBER}.
The deploy step uses JSON Patch to set the container image to the
specific build number tag, making deployments deterministic and
compatible with Terraform (which should ignore_changes on the image).

.drone.yml

@@ -23,13 +23,15 @@ steps:
       repo: viktorbarzin/immoweb
       dockerfile: frontend/Dockerfile
       context: frontend
-      auto_tag: true
+      tags:
+        - latest
+        - ${DRONE_BUILD_NUMBER}
 
   - name: Update deployment
     image: alpine
     commands:
       - apk add curl
-      - 'curl -X PATCH https://kubernetes:6443/apis/apps/v1/namespaces/realestate-crawler/deployments/realestate-crawler-ui -H "Authorization:Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" -H "Content-Type:application/strategic-merge-patch+json" -k -d ''{"spec": {"template": {"metadata": { "annotations": {"kubectl.kubernetes.io/restartedAt": "''$(date +%Y-%m-%dT%TZ)''" }}}}}'' | head'
+      - 'curl -s -X PATCH "https://kubernetes:6443/apis/apps/v1/namespaces/realestate-crawler/deployments/realestate-crawler-ui" -H "Authorization: Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" -H "Content-Type: application/json-patch+json" -k -d ''[{"op":"replace","path":"/spec/template/spec/containers/0/image","value":"viktorbarzin/immoweb:''"$DRONE_BUILD_NUMBER"''"}]'' | head'
 
 ---
 kind: pipeline
@@ -57,11 +59,13 @@ steps:
       repo: viktorbarzin/realestatecrawler
       dockerfile: Dockerfile
       context: .
-      auto_tag: true
+      tags:
+        - latest
+        - ${DRONE_BUILD_NUMBER}
       cache_from: viktorbarzin/realestatecrawler:latest
 
   - name: Update deployment
     image: alpine
     commands:
       - apk add curl
-      - 'curl -X PATCH https://kubernetes:6443/apis/apps/v1/namespaces/realestate-crawler/deployments/realestate-crawler-api -H "Authorization:Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" -H "Content-Type:application/strategic-merge-patch+json" -k -d ''{"spec": {"template": {"metadata": { "annotations": {"kubectl.kubernetes.io/restartedAt": "''$(date +%Y-%m-%dT%TZ)''" }}}}}'' | head'
+      - 'curl -s -X PATCH "https://kubernetes:6443/apis/apps/v1/namespaces/realestate-crawler/deployments/realestate-crawler-api" -H "Authorization: Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" -H "Content-Type: application/json-patch+json" -k -d ''[{"op":"replace","path":"/spec/template/spec/containers/0/image","value":"viktorbarzin/realestatecrawler:''"$DRONE_BUILD_NUMBER"''"}]'' | head'