release: v4.0.2 (#4801)

* Disable BROWSER env var

Right now the browser helper script does not actually work.  It seems
safer to skip this until we can fix it.

* Bump to 4.0.2

* Update changelog for 4.0.2

docs/manifest.json

@@ -1,5 +1,5 @@
 {
-  "versions": ["v4.0.1"],
+  "versions": ["v4.0.2"],
   "routes": [
     {
       "title": "Home",