Update upstream source from tag 'upstream/2.0.4'

.circleci/config.yml

.gitignore

.prospector.yaml

README.md

docs/source/conflict_handling.rst

docs/source/indexes.rst

docs/source/installation.rst

docs/source/table_partitioning.rst

psqlextra/__init__.py

psqlextra/backend/introspection.py

psqlextra/backend/migrations/operations/__init__.py

...extra/backend/migrations/operations/add_hash_partition.py

...backend/migrations/operations/create_partitioned_model.py

...ra/backend/migrations/operations/delete_hash_partition.py

psqlextra/backend/migrations/operations/partition.py

psqlextra/backend/migrations/patched_autodetector.py

psqlextra/backend/migrations/state/__init__.py

psqlextra/backend/migrations/state/partitioning.py

psqlextra/backend/schema.py

psqlextra/compiler.py