Re-add Docker image to release pipeline (#3155)

## Summary

I already re-created and pushed the image, and set its visibility to
public (it defaults to private) -- see:
https://github.com/astral-sh/uv/pkgs/container/uv.

Closes https://github.com/astral-sh/uv/issues/2774.

.github/workflows/release.yml

@@ -92,11 +92,24 @@ jobs:
       plan: ${{ needs.plan.outputs.val }}
     secrets: inherit
 
+  custom-build-docker:
+    needs:
+      - plan
+    if: ${{ needs.plan.outputs.publishing == 'true' || fromJson(needs.plan.outputs.val).ci.github.pr_run_mode == 'upload' || inputs.tag == 'dry-run' }}
+    uses: ./.github/workflows/build-docker.yml
+    with:
+      plan: ${{ needs.plan.outputs.val }}
+    secrets: inherit
+    permissions:
+      packages: write
+      contents: read
+
   # Build and package all the platform-agnostic(ish) things
   build-global-artifacts:
     needs:
       - plan
       - custom-build-binaries
+      - custom-build-docker
     runs-on: "ubuntu-20.04"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}