Fix implicit dependency on isomorphic-ws

This previously worked because a) it was a dev dep and b) it's a dep
of websocket-stream, which is an explicit dependency, but it's better
to properly include it here.

Author: pimterry

package.json

@@ -126,7 +126,6 @@
     "fs-extra": "^8.1.0",
     "http-proxy-agent": "^2.0.0",
     "https-proxy-agent": "^2.2.1",
-    "isomorphic-ws": "^4.0.1",
     "karma": "^6.3.2",
     "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^2.2.0",
@@ -177,6 +176,7 @@
     "graphql-tag": "^2.12.6",
     "http-encoding": "^1.5.0",
     "http2-wrapper": "2.0.5",
+    "isomorphic-ws": "^4.0.1",
     "lodash": "^4.16.4",
     "native-duplexpair": "^1.0.0",
     "node-forge": "^1.2.1",