Log Message:
databases/py-peewee: Update to 3.3.4.

3.3.4
- Added a BinaryUUIDField class for efficiently storing UUIDs in
  16-bytes.
- Fix dataset's update_cache() logic so that when updating a single
  table that was newly-added, we also ensure that all dependent tables
  are updated at the same time.

3.3.3
- More efficient implementation of model dependency-graph generation.
  Improves performance of recursively deleting related objects by
  omitting unnecessary subqueries.
- Added union(), union_all(), intersect() and except_() to the
  Model-specific query implementations. This was an oversight that
  should have been patched in 3.3.2, but is fixed in 3.3.3.
- Major cleanup to test runner and standardized test skipping logic to
  integrate with standard-library unittest conventions.

3.3.2
- Add methods for union(), union_all, intersect() and except_().
  Previously, these methods were only available as operator overloads.
- Removed some Python 2.6-specific support code, as 2.6 is no longer
  officially supported.
- Fixed model-graph resolution logic for deferred foreign-keys.
- Better support for UPDATE...FROM queries (Postgresql).