Update http-client requirement from 5 to 6

Updates the requirements on [http-client](https://github.com/http-rs/http-client) to permit the latest version.
- [Release notes](https://github.com/http-rs/http-client/releases)
- [Changelog](https://github.com/http-rs/http-client/blob/main/CHANGELOG.md)
- [Commits](https://github.com/http-rs/http-client/commits)

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

wikibase/Cargo.toml

@@ -15,7 +15,7 @@ argh = "0.1"
 async-std = { version = "1", features = ["attributes"] }
 async-h1 = "2"
 chrono = "0.4"
-http-client = { version = "5", features = ["h1_client"] }
+http-client = { version = "6", features = ["h1_client"] }
 http-types = "2"
 oxigraph = { version = "0.1", path ="../lib", features = ["rocksdb", "http_client"] }
 serde_json = "1"