v0.13.0 - Cusstom post-processing shaders and backdrop filters

What's Changed

• feat: custom shaders by @antouhou in #35
• fix: nested effects rendering by @antouhou in #36
• chore: split renderer into separate files by @antouhou in #37
• chore: remove all heap allocation from the hot renderer loop by @antouhou in #38
• refactor: optimization: simplified pipeline for rectangles by @antouhou in #39

Full Changelog: v0.12.0...v0.13.0