build(deps): update quick-xml requirement from 0.30 to 0.31

Updates the requirements on [quick-xml](https://github.com/tafia/quick-xml) to permit the latest version.
- [Release notes](https://github.com/tafia/quick-xml/releases)
- [Changelog](https://github.com/tafia/quick-xml/blob/master/Changelog.md)
- [Commits](tafia/quick-xml@v0.30.0...v0.31.0)

---
updated-dependencies:
- dependency-name: quick-xml
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

gtk4-macros/Cargo.toml

@@ -21,7 +21,7 @@ blueprint = []
 
 [dependencies]
 anyhow = "1.0"
-quick-xml = {version = "0.30", optional = true}
+quick-xml = {version = "0.31", optional = true}
 proc-macro-crate = "2.0"
 proc-macro-error = "1.0"
 proc-macro2 = "1.0"