Update glib-macros requirement from 0.18 to 0.19

Updates the requirements on [glib-macros](https://github.com/gtk-rs/gtk-rs-core) to permit the latest version.
- [Release notes](https://github.com/gtk-rs/gtk-rs-core/releases)
- [Changelog](https://github.com/gtk-rs/gtk-rs-core/blob/master/CHANGELOG.md)
- [Commits](gtk-rs/gtk-rs-core@0.18.0...0.18.5)

---
updated-dependencies:
- dependency-name: glib-macros
  dependency-type: direct:production
...

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

Author: dependabot[bot]

examples/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-glib-macros = "0.18"
+glib-macros = "0.19"
 once_cell = "1.17.1"
 
 [dependencies.granite]