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-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/ogc.yml

@@ -56,7 +56,7 @@ jobs:
 
       - name: Build Docker Container
         id: docker-build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           tags: qgis/qgis-deps-ogc:${{ github.event.pull_request.base.ref || github.ref_name }}
           context: .ci/ogc

.github/workflows/run-tests.yml

@@ -124,7 +124,7 @@ jobs:
 
       - name: Build Docker Container with Build Environment
         id: docker-build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: .docker/qgis3-qt${{ matrix.qt-version }}-build-deps.dockerfile
@@ -355,7 +355,7 @@ jobs:
 
       - name: Build Docker Container with Testing Environment
         id: docker-build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: .docker/qgis3-qt${{ matrix.qt-version }}-build-deps.dockerfile
@@ -466,7 +466,7 @@ jobs:
 
       - name: Build Docker Container with Testing Environment
         id: docker-build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: .docker/qgis3-qt${{ matrix.qt-version }}-build-deps.dockerfile