Update ffi dependency

Author: bennetthardwick

package-lock.json

@@ -23,7 +23,7 @@
   "author": "Bennett Hardwick <[email protected]> (bennetthardwick.com)",
   "license": "MIT",
   "dependencies": {
-    "ffi": "git+https://github.com/node-ffi/node-ffi.git",
+    "ffi": "^2.3.0",
     "ref": "^1.3.5",
     "ref-struct": "^1.1.0",
     "rxjs": "^6.2.1",