chore: update node-forge to ^0.9.1 (#941)

As commnented on #934 (comment)

Given that node-forge is a 0.x version, npm considers it to be a breaking change, and hence not compatible with the current requirement.

node-forge is also transitively being used by firestore (direct dependency is google-p12-pem), and requiring version ^0.9.0, which means two copies of the library are currently needed. Switching to just one dependency would save 1.7Mib.

Author: sk-

package-lock.json

@@ -58,7 +58,7 @@
     "@types/node": "^10.10.0",
     "dicer": "^0.3.0",
     "jsonwebtoken": "^8.5.1",
-    "node-forge": "^0.7.6"
+    "node-forge": "^0.9.1"
   },
   "optionalDependencies": {
     "@google-cloud/firestore": "^4.0.0",