build(deps): update async-tls requirement from 0.11 to 0.12

Updates the requirements on [async-tls](https://github.com/async-std/async-tls) to permit the latest version.
- [Release notes](https://github.com/async-std/async-tls/releases)
- [Commits](async-rs/async-tls@v0.11.0...v0.12.0)

---
updated-dependencies:
- dependency-name: async-tls
  dependency-type: direct:production
...

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

Author: dependabot[bot]

examples/Cargo.toml

@@ -17,7 +17,7 @@ path = "../glib"
 path = "../gio"
 
 [dependencies.async-tls]
-version = "0.11"
+version = "0.12"
 optional = true
 
 [build-dependencies.glib-build-tools]