Prepare 1.4.0 release

Author: sagebind

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "isahc"
-version = "1.3.1"
+version = "1.4.0"
 description = "The practical HTTP client that is fun to use."
 authors = ["Stephen M. Coakley <[email protected]>"]
 license = "MIT"

README.md

@@ -70,7 +70,7 @@ Install via Cargo by adding to your `Cargo.toml` file:
 
 ```toml
 [dependencies]
-isahc = "1.3"
+isahc = "1.4"
 ```
 
 ### Minimum supported Rust version

src/lib.rs

@@ -144,7 +144,7 @@
 //!
 //! ```toml
 //! [dependencies.isahc]
-//! version = "1.3"
+//! version = "1.4"
 //! features = ["psl"]
 //! ```
 //!