Update env.py

[kjaymiller]

fixes #284

With this being generated by the environment file I would like to propose another potential fix to ignore the issue either with:

1 - manually with a # ruff: noqa appended to the top of the file.
or
2 - We can also modify the `extend-exclude to include ALL files in the migrations (and not just the version info)

1 doesn't solve the issue long term either as if we ever need to regenerate the file the problem would appear again (which is the concern currently)

2 is a little better but this fix is harmless.

I do wonder if this is something that could be fixed on the alembic end (unless they specifically chose not to fix it)

[pamelafox]

Here's my PR where I previously made style changes to env.py:
miguelgrinberg/Flask-Migrate#504 (comment)

As you can see, my suggestion to fully match the style of isort wasn't taken up on, so I would say that yes, they specifically choose not to fix it.

That's why I ended up doing an exclude, since I really quickly ran into style issues when I updated the migrations.

So am a fan of #2