ci: revert db docker image to only amd64

Author: NGPixel

.github/workflows/dev-db-nightly.yml

@@ -57,7 +57,8 @@ jobs:
         with:
           context: .
           file: docker/db.Dockerfile
-          platforms: linux/amd64,linux/arm64
+          platforms: linux/amd64
+          # platforms: linux/amd64,linux/arm64
           push: true
           tags: |
             ghcr.io/ietf-tools/datatracker-db:nightly-${{ steps.date.outputs.date }}