Revert "dependencies: Upgrade webpack-dev-server to v3.4.1."

This seems to have broken the development server.

This reverts commit daf8dd1960.

package.json

@@ -72,7 +72,7 @@
     "stylelint": "9.3.0",
     "svgo": "1.0.5",
     "swagger-parser": "3.4.1",
-    "webpack-dev-server": "3.4.1",
+    "webpack-dev-server": "3.1.4",
     "xmlhttprequest": "1.8.0"
   },
   "scripts": {

version.py

@@ -11,4 +11,4 @@ LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2019/03/01/zulip-2-0-relea
 # Typically, adding a dependency only requires a minor version bump, and
 # removing a dependency requires a major version bump.
 
-PROVISION_VERSION = '32.3'
+PROVISION_VERSION = '33.0'