If you need to have your own full Google Drive Connector, you need to get your GD API keys. You can obtain them in Google Developers Console.
You can create a new project there and name it as you wish:
After creating project, you need to create credentials for your project.
Use OAuth client ID.
Set a name of your new app as you wish.
After setting a name you can finally create the Credentials for OAuth2 client ID. Be sure to set Authorised Redirect URIs: https://preview.powerbi.com/views/oauthredirect.html
Now you can download you .mez connector file from here. Open PQGoogleSpreadsheet - empty.mez.zip in your favourite ZIP editor and copy your Client ID to client_id.txt file and your Client Secret to client_secret.txt file.
Be sure that you saved the archive. And then remove .zip extension from file. It meens you need to rename PQGoogleSpreadsheet - empty.mez.zip to PQGoogleSpreadsheet.mez.
Finally copy your new connector file PQGoogleSpreadsheet.mez to Documents\Microsoft Power BI Desktop\Custom Connectors\ folder and restart Power BI.
You'll be able to see your new connector amongst Power BI Connectors. To get to the Google Spreadsheet file you need just copy & paste spreadsheet url.