Update http-serde requirement from 1.1.2 to 2.1.1

Updates the requirements on [http-serde](https://gitlab.com/kornelski/http-serde) to permit the latest version.
- [Commits](https://gitlab.com/kornelski/http-serde/compare/v1.1.2...v2.1.1)

---
updated-dependencies:
- dependency-name: http-serde
  dependency-type: direct:production
...

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

Cargo.toml

@@ -13,7 +13,7 @@ description = "nickserv account verification URL bot"
 clap = { version = "4.5.9", features = ["derive"] }
 dxr_client = { version = "0.6.2", features = ["reqwest"] }
 http = "0.2.12" # warp is stuck on an old version
-http-serde = "1.1.3"
+http-serde = "2.1.1"
 hyper = "1.4.1"
 regex = "1.10.5"
 reqwest = "0.12.5"