Bump docker/build-push-action from 4 to 5

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 4 to 5.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v4...v5)

---
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/E2Etests.yml

@@ -32,7 +32,7 @@ jobs:
           path: beacon-network
 
       - name: Build Backend
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v5
         with:
           context: ./beacon-network
           push: true
@@ -73,7 +73,7 @@ jobs:
           ./tests/test_files/add_fixtures.sh
 
       - name: Build Frontend
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v5
         with:
           context: .
           build-args: |