`--no-default-features` build fails to compile (`HttpWithBody` / `HttpErrorStatus` cfg mismatch)

[joeblew999]

On a clean master (v3.9.6), a --no-default-features build fails:

$ cargo build --no-default-features
error[E0425]: cannot find type `HttpErrorStatus` in this scope
   --> src/error.rs:126:17
error[E0004]: non-exhaustive patterns: `&error::Error::HttpWithBody { .. }` not covered
   --> src/error.rs:205:15

Cause: in src/error.rs the HttpWithBody variant is ungated, but its field type
HttpErrorStatus and the matching classify() arm are both #[cfg(feature = "reqwest")]. Without
reqwest the variant references a type that doesn't exist (E0425) and the classify() match becomes
non-exhaustive (E0004).

Fix: gate the variant to match its field/arm — one line:

#[cfg(feature = "reqwest")]   // <-- add
#[error("HTTP error {status}: {body:?}")]
#[diagnostic(code(google_maps::http_with_body))]
HttpWithBody { status: HttpErrorStatus, body: String },

Happy to send a PR. (Same fix referenced in #44 §1, but it's independent of the Workers work and can
land on its own.)