FIX: FCM pushes fixed due to deprecation of legacy api (#292)

* FIX: FCM pushes fixed due to deprecation of legacy  api

README.md

@@ -87,18 +87,22 @@ Works well on Heroku (you'll need `JawsDB Maria` addon)
 Set them as env variables or put them into `.env` file in project root dir.
 
 - `JAWSDB_MARIA_URL` for example `mysql://username:password@host:port/database`
-- `FCM_SERVER_KEY` hex encoded
+- ~~`FCM_SERVER_KEY` hex encoded~~ deprecated (in favor of json key file) after FCM XMPP and HTTP legacy APIs was deprecated; the new one is HTTP v1 API; theres also a new uri to post payload
 - `APNS_P8` hex encoded
 - `APNS_P8_KID` issuer key which is "key ID" of your p8 file
 - `APPLE_TEAM_ID` "team ID" of your developer account
 - `BITCOIN_RPC` for example `http://username:password@host:8332`
 - `APNS_TOPIC` for example `io.bluewallet.bluewallet`
+- `GOOGLE_KEY_FILE` - json file with Google key for FCM, in hex
+- `GOOGLE_PROJECT_ID` - acquired with the key file
+
 
 ### Getting certificates
 
 - outdated https://dev.to/jakubkoci/react-native-push-notifications-313i
 - https://stackoverflow.com/questions/44631803/ios-swift-how-to-create-p8-file/67533665#67533665
-- get P8 hex `xxd -p file.p8 | tr -d '\n'`
+- get P8 hex `xxd -p file.p8 | tr -d '\n'` (google key file as well)
+- https://firebase.google.com/docs/cloud-messaging/migrate-v1
 
 ### License