Update glyphon with more performance improvements

See:
  - grovesNL/glyphon#90
  - grovesNL/glyphon#91

Author: hecrj

Cargo.toml

@@ -129,7 +129,7 @@ cosmic-text = "0.10"
 dark-light = "1.0"
 futures = "0.3"
 glam = "0.25"
-glyphon = { git = "https://github.com/hecrj/glyphon.git", branch = "use-staging-belt" }
+glyphon = { git = "https://github.com/hecrj/glyphon.git", rev = "6caf269e3cd302a802de1b60958a8404b3ea0dd8" }
 guillotiere = "0.6"
 half = "2.2"
 image = "0.24"