Bump syn from 1.0.98 to 1.0.99 (#1540)

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.98 to 1.0.99.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](dtolnay/syn@1.0.98...1.0.99)

---
updated-dependencies:
- dependency-name: syn
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Cargo.lock

@@ -9,7 +9,7 @@ description = "Proc macros provided by the parachain-system pallet"
 proc-macro = true
 
 [dependencies]
-syn = "1.0.96"
+syn = "1.0.99"
 proc-macro2 = "1.0.42"
 quote = "1.0.21"
 proc-macro-crate = "1.1.3"