build(deps): update eframe requirement from 0.26 to 0.28

Updates the requirements on [eframe](https://github.com/emilk/egui) to permit the latest version.
- [Release notes](https://github.com/emilk/egui/releases)
- [Changelog](https://github.com/emilk/egui/blob/master/CHANGELOG.md)
- [Commits](emilk/egui@0.26.0...0.28.1)

---
updated-dependencies:
- dependency-name: eframe
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -18,7 +18,7 @@ egui26 = { version = "0.26", package = "egui", default-features = false, optiona
 egui27 = { version = "0.27", package = "egui", default-features = false, optional = true }
 
 [dev-dependencies]
-eframe = "0.26"
+eframe = "0.28"
 
 [features]
 default = [ "egui26" ]