feat: default to charset=utf-8 for text content type (#554)

* feat: default to charset=utf-8 for text content type

* added changelog && fix comment

* fix workflow

examples/testing/Cargo.toml

@@ -6,9 +6,10 @@ publish = false
 
 [dependencies]
 axum = { path = "../../axum" }
+mime = "0.3"
 tokio = { version = "1.0", features = ["full"] }
 tracing = "0.1"
-tracing-subscriber = { version="0.3", features = ["env-filter"] }
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tower-http = { version = "0.1", features = ["trace"] }
 serde_json = "1.0"
 hyper = { version = "0.14", features = ["full"] }

examples/testing/src/main.rs

@@ -81,7 +81,7 @@ mod tests {
                 Request::builder()
                     .method(http::Method::POST)
                     .uri("/json")
-                    .header(http::header::CONTENT_TYPE, "application/json")
+                    .header(http::header::CONTENT_TYPE, mime::APPLICATION_JSON.as_ref())
                     .body(Body::from(
                         serde_json::to_vec(&json!([1, 2, 3, 4])).unwrap(),
                     ))