Make oauth token field a password field

src/index.html

@@ -29,7 +29,7 @@ <h1>GitHub Changelog Generator</h1>
 
     <p title="You will be limited to only 60 requests per hour if you do not provide a token, otherwise 5000."
         >OAuth2 Token
-        <input type="text" id="authtoken">
+        <input type="password" id="authtoken">
         <a href="https://developer.github.com/v3/oauth_authorizations/#create-a-new-authorization">Help</a>
     </p>