v1.0.0

This marks the first release since this repo was rolled out of wgpu-py. Compared to the version in wgpu-py, this code underwent the following changes:

• Obvious renaming, e.g. WgpuCanvas -> RenderCanvas.
• The canvas.get_context() must be called with canvas.get_context("wgpu").
• The above means that the canvas can also be used by other rendering systems.
• We provide a bitmap-based context canvas.get_context("bitmap") out of the box.
• Add backends for qt libs, e.g. from rendercanvas.pyside6 import RenderCanvas.
• New scheduling system that is implemented generally instead of separate for each backend, and is generally better in several ways.
• Multiple different update modes are supported.
• The backend system is much better defined, and a few bugs were fixed in this process.
• Don't call asyncio.get_event_loop(), because its deprecated now.