Update docker/build-push-action action to v6 (#855)

Author: renovate[bot]

.github/workflows/build_docker.yml

@@ -58,7 +58,7 @@ jobs:
 
       - name: Build and push Docker Image
         if: ${{ steps.changed-files.outputs.any_changed == 'true' }}
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./
           file: ./server.Dockerfile
@@ -121,7 +121,7 @@ jobs:
 
       - name: Build and push Docker Image
         if: ${{ steps.changed-files.outputs.any_changed == 'true' }}
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./
           file: ./client.Dockerfile