Bump serial_test from 3.0.0 to 3.1.1

Bumps [serial_test](https://github.com/palfrey/serial_test) from 3.0.0 to 3.1.1.
- [Release notes](https://github.com/palfrey/serial_test/releases)
- [Commits](palfrey/serial_test@v3.0.0...v3.1.1)

---
updated-dependencies:
- dependency-name: serial_test
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Cargo.lock

@@ -37,7 +37,7 @@ url = "2.5"
 env_logger = "0.11"
 invalidstring = { path = "../invalidstring", version = "0.1" }
 pretty_assertions = "1.4"
-serial_test = "3.0"
+serial_test = "3.1"
 tempfile = "3"
 
 [features]