Update syn requirement from 1.0.80 to 2.0.5

Updates the requirements on [syn](https://github.com/dtolnay/syn) to permit the latest version.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](dtolnay/syn@1.0.80...2.0.5)

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

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

macros/Cargo.toml

@@ -19,7 +19,7 @@ license = "Apache-2.0 OR MIT"
 proc-macro = true
 
 [dependencies.syn]
-version = "1.0.80"
+version = "2.0.5"
 
 [dependencies.quote]
 version = "1.0.10"