Update trybuild requirement from =1.0.85 to =1.0.88 (#61)

Updates the requirements on [trybuild](https://github.com/dtolnay/trybuild) to permit the latest version.
- [Release notes](https://github.com/dtolnay/trybuild/releases)
- [Commits](dtolnay/trybuild@1.0.85...1.0.88)

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

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

Cargo.toml

@@ -36,5 +36,5 @@ futures-executor = "0.3.15"
 gotham = { version = "0.7", features = ["testing"], default-features = false }
 percent-encoding = "2.1"
 pretty_env_logger = "0.5"
-trybuild = "=1.0.85"
+trybuild = "=1.0.88"
 validator = { version = "0.16", features = ["derive"] }