Update docker/build-push-action digest to 31159d4 (#34)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/docker.yml

@@ -25,7 +25,7 @@ jobs:
           images: clivern/badger
 
       - name: Build and push Docker image
-        uses: docker/build-push-action@94f8f8c2eec4bc3f1d78c1755580779804cb87b2
+        uses: docker/build-push-action@31159d49c0d4756269a0940a750801a1ea5d7003
         with:
           context: .
           file: ./Dockerfile