websocket support in dev (#150)

* websocket support

This resuscitates threepointone/nu-wrangler#19 via @Electroid. This probably needs tests, in a future PR. But it works well!

* Add a changeset

* update changeset

.changeset/fuzzy-dancers-nail.md

@@ -0,0 +1,5 @@
+---
+"wrangler": patch
+---
+
+Add support for websockets in `dev`, i.e. when developing workers. This replaces the proxy layer that we use to connect to the 'edge' during preview mode, using the `faye-wesocket` library.

packages/wrangler/package.json

@@ -47,17 +47,18 @@
   "devDependencies": {
     "@iarna/toml": "^2.2.5",
     "@types/react": "^17.0.37",
+    "@types/serve-static": "^1.13.10",
     "@types/signal-exit": "^3.0.1",
     "@types/ws": "^8.2.1",
     "@types/yargs": "^17.0.7",
     "chokidar": "^3.5.2",
     "clipboardy": "^3.0.0",
     "command-exists": "^1.2.9",
     "execa": "^6.0.0",
+    "faye-websocket": "^0.11.4",
     "finalhandler": "^1.1.2",
     "find-up": "^6.2.0",
     "formdata-node": "^4.3.1",
-    "http-proxy": "^1.18.1",
     "ink": "^3.2.0",
     "ink-select-input": "^4.2.1",
     "ink-table": "^3.0.0",