Add feature flag

・add `rocket_support` feature flag

Author: nanato12

Cargo.toml

@@ -11,9 +11,12 @@ license-file = "LICENSE"
 keywords = ["line", "linebot", "line-bot-sdk", "line-messaging-api"]
 categories = ["api-bindings"]
 
+[features]
+default = []
+rocket_support = ["rocket"]
 
 [dependencies]
-rocket = "0.4"
+rocket = { version = "0.4", optional = true }
 reqwest = { version = "0.11.0", features = ["blocking", "json"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

src/support/mod.rs

@@ -1,3 +1,4 @@
 //! Support for framework
 
+#[cfg(feature = "rocket_support")]
 pub mod rocket_support;