Update databrickslabs/sandbox requirement to acceptance/v0.3.1

Updates the requirements on [databrickslabs/sandbox](https://github.com/databrickslabs/sandbox) to permit the latest version.
- [Release notes](https://github.com/databrickslabs/sandbox/releases)
- [Changelog](https://github.com/databrickslabs/sandbox/blob/main/CHANGELOG.md)
- [Commits](https://github.com/databrickslabs/sandbox/commits/acceptance/v0.3.1)

---
updated-dependencies:
- dependency-name: databrickslabs/sandbox
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/downstreams.yml

@@ -46,7 +46,7 @@ jobs:
         run: |
           pip install hatch==1.9.4
       - name: Downstreams
-        uses: databrickslabs/sandbox/downstreams@downstreams/v0.0.1
+        uses: databrickslabs/sandbox/downstreams@acceptance/v0.3.1
         with:
           repo: ${{ matrix.downstream.name }}
           org: databrickslabs