test: --tag next for prerelease publish (test branch only)

Author: Isonimus

.github/workflows/publish.yml

@@ -47,4 +47,4 @@ jobs:
       # `--provenance` flag is implied under Trusted Publishing but kept
       # explicit for readability.
       - name: Publish to npm
-        run: npm publish --access public --provenance
+        run: npm publish --access public --provenance --tag next