Use proxy in GCM connection

[simonegiacco]

Hello,
I need to use a proxy while connecting to the fcm.googleapis.com server.

The package parse-community/node-gcm supports the use of a proxy for the connection, but parse-server-push-adapter is not passing this configuration.

We have found the solution and will send a PR soon

[simonegiacco]

PR #153

push configuration will be like this:

"push": {
    "android": {
      "apiKey": "AAAAXOL3MDw:APA.....",
      "requestOptions": {
        "proxy": "http://localhost:8080",
        "timeout": 1000
      }
    }
  }

[dplewis]

Closing via #153