Update django-extensions to 2.0.0

[pyup-bot]

There's a new version of django-extensions available.
You are currently using 1.9.9. I have updated it to 2.0.0

These links might come in handy: PyPI | Changelog | Repo | Docs

Changelog

2.0.0

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Changes:

• Fix: runserver_plus, for 1.11 still using MIDDLEWARE_CLASSES
• Fix: show_urls, Fix display in Django 2.0
• Fix: validate_templates, remove realpath in validate_templates
• Fix: sqldiff, bug with including proxy models in sqldiff output
• Improvement: shell_plus, allow configurating of sqlparse formatting and pygments formatting
• Improvement: shell_plus, add collision resolvers based on app label
• Improvement: shell_plus, automatic importing of subclasses defined in SHELL_PLUS_SUBCLASSES_IMPORT
• New: reset_schema, simple command to recreate public schema in PostgreSQL
• Docs: fix links to Werkzeug documentation

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

[pyup-bot]

Closing this in favor of #186