***Note from Migration:***
Original Title was: Google BigQuery Package: Add an optional parameter to Google BigQuery Writer to specify Service Account Key File Path
The Google BigQuery writer has an option to use a Service Account Key File to authenticate Google BigQuery connection.
In my observation, if you use a Service Account Key File, you have to define an environment variable called GOOGLE_APPLICATION_CREDENTIALS in your system to specify its file path, so you need to modify the variable whenever you run the workspace for different project. Also there could be a case where you aren't allowed to define the environment variable in the server system due to the limits of your user permissions.
It would be better if the key file path could be specify through a writer parameter explicitly.