chore(deps): update syn requirement from 1.0.42 to 2.0.40

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@1.0.42...2.0.40)

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

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

derive-impl/Cargo.toml

@@ -15,5 +15,5 @@ proc-macro2 = { version = "1.0.24", features = ["span-locations"] }
 proc-macro-crate = "2.0.0"
 proc-macro-error = "1.0.4"
 quote = "1.0.7"
-syn = "1.0.42"
+syn = "2.0.40"
 synstructure = "0.12.4"