actions: split image building and publishing to separate steps

.github/workflows/go.yaml

@@ -63,10 +63,15 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-      - name: Publish nightly image
+      - name: Build nightly image
         if: ${{ github.event_name != 'pull_request' }}
         working-directory: ${{ env.working-directory }}
         run: make nightly
 
+      - name: Publish nightly image
+        if: ${{ github.event_name != 'pull_request' }}
+        working-directory: ${{ env.working-directory }}
+        run: make docker-push
+
 # TODO:
 # - E2E

Makefile

@@ -96,4 +96,3 @@ release:
 
 nightly:
 	goreleaser --snapshot --rm-dist --config=.goreleaser-nightly.yml
-	docker push ${IMG}