chore(deps): drop support for Python 3.7 (#84)

* chore(deps): drop support for Python 3.7

In link with the recent release of [Manim v0.17.0](https://github.com/ManimCommunity/manim/releases/tag/v0.17.0), Manim Slides drops support for Python 3.7.

* feat(cli): check for newer Manim Slides version

Uses same logic as manim to check for a new version

* fix(lib): reset correct version

* chore(setup): remove 3.7 classifier

Author: jeertmans

pyproject.toml

@@ -17,7 +17,6 @@ keywords = ["manim", "slides", "plugin", "manimgl"]
 
 classifiers = [
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",