Update changelog and readme for new version

Author: foxbenjaminfox

CHANGELOG.md

@@ -2,6 +2,7 @@
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 # Changelog
 
+- [v3.4.0](#v340)
 - [v3.3.0](#v330)
 - [v3.2.1](#v321)
 - [v3.2.0](#v320)
@@ -19,6 +20,11 @@
 - [v1.0.0](#v100)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+### v3.4.0
+  * Add a `shouldUpdate` option, which can control when and if
+    an async computed property updates.
+
 ### v3.3.0
   * New feature: lazily computed properties.
 

README.md

@@ -102,7 +102,7 @@ Alternately, you can link it directly from a CDN:
   That will always point to the latest version of vue-async-computed.
   You probably want to instead pin it to a specific version:
 -->
-<script src="https://unpkg.com/vue-async-computed@3.3.0"></script>
+<script src="https://unpkg.com/vue-async-computed@3.4.0"></script>
 ````
 
 When used with a module system such as `webpack` or `browserify`, you need to explicitly install `vue-async-computed` via `Vue.use()`: