feat: push the docker image to dockerhub as a tag as well

This will prevent people from just using latest, and potentially breaking their application. Anything up to version 2.0.0 has been pushed as latest, so it will break anything beforet his

.github/workflows/publish_docker_image.yaml

@@ -1,21 +1,31 @@
 name: Publish Docker image
 on:
-  release:
-    types: [published]
+    release:
+        types: [published]
 jobs:
-  push_to_registry:
-    name: Push Docker image to Docker Hub
-    runs-on: ubuntu-latest
-    steps:
-      - name: Check out the repo
-        uses: actions/checkout@v2
-      - name: Log in to Docker Hub
-        uses: docker/login-action@v1
-        with:
-          username: ${{ secrets.DOCKER_USERNAME }}
-          password: ${{ secrets.DOCKER_PASSWORD }}
-      - name: Push to Docker Hub
-        uses: docker/build-push-action@v2
-        with:
-          push: true
-          tags: hemmeligapp/hemmelig:latest
+    push_to_registry:
+        name: Push Docker image to Docker Hub
+        runs-on: ubuntu-latest
+        steps:
+            - name: Check out the repo
+              uses: actions/checkout@v2
+            - name: Log in to Docker Hub
+              uses: docker/login-action@v1
+              with:
+                  username: ${{ secrets.DOCKER_USERNAME }}
+                  password: ${{ secrets.DOCKER_PASSWORD }}
+            - name: Get latest git tag
+              id: latest_tag
+              uses: 'WyriHaximus/github-action-get-previous-tag@v1'
+              with:
+                  fallback: no-tag
+            - name: Push to Docker Hub
+              uses: docker/build-push-action@v2
+              with:
+                  push: true
+                  tags: hemmeligapp/hemmelig:latest
+            - name: Push to Docker Hub
+              uses: docker/build-push-action@v2
+              with:
+                  push: true
+                  tags: hemmeligapp/hemmelig:${{ steps.latest_tag.outputs.tag }}