⬆️ Update attohttpc requirement from ^0.26 to ^0.28

Updates the requirements on [attohttpc](https://github.com/sbstp/attohttpc) to permit the latest version.
- [Release notes](https://github.com/sbstp/attohttpc/releases)
- [Commits](sbstp/attohttpc@v0.26.0...v0.28.0)

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

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

Cargo.toml

@@ -21,7 +21,7 @@ exclude = [
 ]
 
 [dependencies]
-attohttpc = { version = "^0.26", optional = true, default-features = false, features = [
+attohttpc = { version = "^0.28", optional = true, default-features = false, features = [
     "compress",
     "tls-rustls-webpki-roots",
 ] }