chore(release): bump to v0.2.0a3 — fifth PyPI alpha

Ships the batch merged since 0.2.0a2:
- SECURITY: SW message-handler origin check (#208, CodeQL
  js/missing-origin-check) — the artifact's service worker now
  rejects cross-origin cache-control messages.
- PWA backend serving (#200), React login form end-to-end (#190),
  create/Add form completing CRUD (#199), autocomplete FK widget
  (#207), date_hierarchy drill-down (#205), action-label + list
  cosmetics fixes (#203/#204), lint cleanup (#202).

368 tests pass. Tier 6 — version bump; publish via the Security
deploy-gate under the standing "deploy regularly if secure" directive.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: martin-castro-laminr-ai

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "django-admin-react"
-version = "0.2.0a2"
+version = "0.2.0a3"
 description = "A drop-in React single-page admin for Django, driven entirely by ModelAdmin."
 authors = ["django-admin-react contributors"]
 license = "MIT"