build(deps): update rcgen requirement from 0.12 to 0.13

Updates the requirements on [rcgen](https://github.com/rustls/rcgen) to permit the latest version.
- [Commits](https://github.com/rustls/rcgen/compare/v0.12.0...v0.13.1)

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

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

actix-tls/Cargo.toml

@@ -131,7 +131,7 @@ bytes = "1"
 pretty_env_logger = "0.5"
 futures-util = { version = "0.3.17", default-features = false, features = ["sink"] }
 itertools = "0.13"
-rcgen = "0.12"
+rcgen = "0.13"
 rustls-pemfile = "2"
 tokio-rustls-026 = { package = "tokio-rustls", version = "0.26" }
 trust-dns-resolver = "0.23"