dependabot: bump docker/build-push-action from 3 to 4

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 3 to 4.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v3...v4)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/backend.yml

@@ -54,7 +54,7 @@ jobs:
 
       - if: ${{ github.ref == 'refs/heads/staging' }}
         name: Build staging image
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           context: .
           builder: ${{ steps.buildx.outputs.name }}
@@ -68,7 +68,7 @@ jobs:
 
       - if: ${{ github.ref == 'refs/heads/main' }}
         name: Build production image
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           context: .
           builder: ${{ steps.buildx.outputs.name }}

.github/workflows/feature-based.yaml

@@ -49,7 +49,7 @@ jobs:
             ${{ runner.os }}-single-buildx
 
       - name: Build staging image
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           context: .
           builder: ${{ steps.buildx.outputs.name }}