build(deps): bump docker/build-push-action from 2 to 2.4.0 (#866)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2 to 2.4.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v2...v2.4.0)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build-multiarch.yml

@@ -64,7 +64,7 @@ jobs:
 
       - name: Build and push
         id: docker_build
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@v2.4.0
         with:
           context: .
           file: ./Dockerfile

.github/workflows/main.yml

@@ -75,7 +75,7 @@ jobs:
 
     - name: Build and push
       id: docker_build
-      uses: docker/build-push-action@v2
+      uses: docker/build-push-action@v2.4.0
       with:
         context: .
         file: ./Dockerfile