Switch to Pyglet 2.1 or dev releases

[pushfoo]

TL;DR: Get new pyglet bug fixes + immutable vecs for #2021

Why?

Per Discord discussion with @Cleptomania, this change:

1. enables backward-compatible BasicSprite.scale behavior in Name scale properties on Sprites to things that make sense #2021:

   # Will work with scalars as it does now
   sprite_instance.scale *= 2.0
   # Cleaner & more efficient than setting individual scale components
   sprite_instance.scale *= 2.0, 3.0

2. seems to show it works fine according to preliminary tests
3. matches how we've never made a release that wasn't on a preview pyglet build

Changes

1. Use pyglet==2.1dev2
2. Update references to pyglet.canvas to refer to pyglet.display
3. Use new layout syntax per 2.1 styles

Testing Steps Taken

• Human spot-check of examples (GUI, Text, and Media) on

  • Linux
  • Windows
  • Mac

• Run unit & integration tests on

  • Linux
  • Windows
  • Mac

Follow-up Work

• Update Name scale properties on Sprites to things that make sense #2021 with BasicSprite changes
• Thorough example / functionality shakedown per the 2.1 migration guide
• (Optional) Make arcade match the x, y, z style of pyglet's text / etc?

[pushfoo]

TL;DR: Looks like CI failures are all unimportant but annoying type annotation issues.

In addition to pre-existing CI failures from the GUI, we also gain a few new ones due to 2.1 changes on pyglet's side:

• The pyglet .pyi file doesn't appear to be updated to reflect s/pyglet.canvas/pyglet.display/g (PyCharm + pyright dislike this) fixed as of 2.1dev2
• In pyglet, Literal used to annotate arguments where str is more appropriate 😢

[pushfoo]

Ben just shipped pyglet 2.1dev2. I plan on updating this branch to that after I get back in < 2 hrs.

[pushfoo]

The recent commits:

1. Resolve rebase conflicts
2. Fix a lingering pyright issue from either the conflict resolution or pyglet 2.0 -> 2.1 changes