Updated Developer Guide (markdown)

Developer-Guide.md

@@ -64,6 +64,8 @@ if you want to run the full integration suite.
 To get JSDoc from GitHub:
 
     $ git clone git://github.com/jsdoc3/jsdoc.git
+    $ cd jsdoc
+    $ git checkout v3.2.2
 
 Again, the `jsdoc` executable, located at the root of `jsdoc` repository,
 should be in your `PATH`.