Update to released mime_guess v2.0

Cargo.toml

@@ -23,7 +23,7 @@ hyper = "0.12.22"
 flate2 = { version = "^1.0.7", default-features = false, features = ["rust_backend"] }
 log = "0.4"
 mime = "0.3.7"
-mime_guess = "2.0.0-alpha.6"
+mime_guess = "2.0"
 serde = "1.0"
 serde_json = "1.0"
 serde_urlencoded = "0.5"

src/multipart.rs

@@ -213,7 +213,7 @@ impl Part {
         let ext = path.extension()
             .and_then(|ext| ext.to_str())
             .unwrap_or("");
-        let mime = mime_guess::get_mime_type(ext);
+        let mime = mime_guess::from_ext(ext).first_or_octet_stream();
         let file = File::open(path)?;
         let field = Part::new(Body::from(file))
             .mime(mime);