build(deps): bump syn from 1.0.103 to 1.0.104

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.103 to 1.0.104.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](dtolnay/syn@1.0.103...1.0.104)

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

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

Author: dependabot[bot]

Cargo.lock

@@ -9,4 +9,4 @@ proc-macro = true
 
 [dependencies]
 quote = "1.0.21"
-syn = { version = "1.0.103", features = ["full"] }
+syn = { version = "1.0.104", features = ["full"] }