chore(deps): bump docker/build-push-action from 5 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/03-build-secure.yml

@@ -105,7 +105,7 @@ jobs:
 
       # ===== STAGE 2: Build Docker Image with Optimizations =====
       - name: 🏗️ Build Docker Image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ${{ matrix.context }}
           file: ${{ matrix.dockerfile }}

.github/workflows/deploy_code_engine.yml

@@ -42,7 +42,7 @@ jobs:
           password: ${{ secrets.IBM_CLOUD_API_KEY }}
 
       - name: Build and push Docker image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./Dockerfile.codeengine

.github/workflows/deploy_complete_app.yml

@@ -159,7 +159,7 @@ jobs:
           password: ${{ secrets.IBM_CLOUD_API_KEY }}
 
       - name: Build and push backend Docker image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./Dockerfile.codeengine
@@ -191,7 +191,7 @@ jobs:
           password: ${{ secrets.IBM_CLOUD_API_KEY }}
 
       - name: Build and push frontend Docker image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./frontend
           file: ./frontend/Dockerfile.frontend

.github/workflows/publish.yml

@@ -34,7 +34,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push frontend
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./frontend
           file: ./frontend/Dockerfile.frontend
@@ -46,7 +46,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - name: Build and push backend
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./backend
           file: ./backend/Dockerfile.backend