py-django-extensions: updated to 2.1.4

Changes 2.1.4:
Fix: shell_plus, fix 1261 check for --notebook-dir=... argument style
Fix: graph_models, Excluded models displayed as an underscore
Fix: set_fake_password, requires_model_validation has been replaced with requires_system_checks since 1.9
Docs: admin_generator, new documentation and examples
Improvement: JSONField, use new from_db_value syntax on Django 2 and up
Improvement: EncryptedTextField, use new from_db_value syntax on Django 2 and up
Improvement: graph_models, add --dot option
Improvement: graph_models, allow to redirect (text) output to file
Improvement: sqldiff, better support for indexes, index_together and unique_together

(adam)