Update manim requirement to >=0.13.1 from ^0.13.1

[hydrobeam]

When trying to use manim-editor with manim v0.14.0, this error would come up:

manim-editor 0.3.8 requires manim<0.14.0,>=0.13.1, but you have manim 0.14.0 which is incompatible.

This is because of the ^ before the manim version, which restricted the version a bit too much. I've changed this to a >= to include future versions too.

https://python-poetry.org/docs/dependency-specification/#caret-requirements

[christopher-besch]

In my experience I've had huge problems with the >= notation. Shouldn't this work too?

Suggested change

	manim = ">=0.13.1"
	manim = "^0"

[hydrobeam]

For most practical reasons that works, but technically the section API PR was introduced relatively recently, so the plugin wouldn't work with older versions of manim. I chose to keep it at v0.13.1 since that was the version where manim_editor was announced in discord.

Also, when manim hits a 1.0 release this would have to be updated again, which may or may not be necessary 🤷

[christopher-besch]

That's actually a very good point, so we can keep your idea. Could you run poetry update and then merge this?
I could do that too but this way the PR is attributed entirely to you.

[christopher-besch]

Thanks a lot for the efforts, @hydrobeam!