use bash magic to get an env var from the package.json

this is shamelessly stolen from work

.gitea/workflows/docker-build.yaml

@@ -11,7 +11,6 @@ env:
 jobs:
   build-docker-image:
     runs-on: ubuntu-latest
-      #if: gitea.ref == 'refs/heads/master'
     container: catthehacker/ubuntu:act-latest
     permissions:
       contents: read
@@ -22,6 +21,8 @@ jobs:
       - name: Log in to the Container registry
         run: docker login -u ${{ env.USER }} -p ${{ secrets.TOKEN }} ${{ env.REGISTRY }}
       - name: Build Container
-        run: docker build -t "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest" .
+        run: docker build -t "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest" -t "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ env.VERSION }}" .
+        env:
+          version: $(cat package.json | awk 'match($0, /version/) {print $2}' | sed 's/[\",]//g') # extracts the version number from the package.json with bash magic
       - name: Push Container
         run: docker push --all-tags "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}"