Fix dead_code Clippy lint with Rust 1.90+ (#52)

> error: struct `CaddyHTTPServerErrors` is never constructed

GUS-W-20017598

Author: dzuelke

buildpacks/static-web-server/src/caddy_config.rs

@@ -38,11 +38,6 @@ pub(crate) struct CaddyHTTPServerRoute {
     pub(crate) handle: Vec<CaddyHTTPServerRouteHandler>,
 }
 
-#[derive(Serialize, Deserialize, Debug)]
-pub(crate) struct CaddyHTTPServerErrors {
-    pub(crate) routes: Vec<CaddyHTTPServerRoute>,
-}
-
 #[derive(Serialize, Deserialize, Debug)]
 #[serde(untagged)]
 pub(crate) enum CaddyHTTPServerRouteMatcher {