chore: bump docker/build-push-action from 2 to 3

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2 to 3.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v2...v3)

---
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]>

Author: dependabot[bot]

.github/workflows/build_prod.yml

@@ -42,7 +42,7 @@ jobs:
 
       # build a docker image
       - name: docker & push image
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@v3
         with:
           context: .
           file: ./Dockerfile

.github/workflows/tests.yml

@@ -56,7 +56,7 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
       - name: Build
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@v3
         with:
           context: .
           file: ./Dockerfile