StrackDriver datasources privateKey

Hi All
My grafana version: 7.2.1

I am trying to work with datasources “stackdriver/cloudmonitoring” follow with https://grafana.com/docs/grafana/latest/datasources/cloudmonitoring/

This datasource allow me to use jwt and with service account json key
I am able to setup the datasource and make grafana grep data from GCP by this

  secureJsonData:
    privateKey: |
       -----BEGIN PRIVATE KEY----
       abdawdaweqwewaee
       awrara3e2ae2ae2
       .....
       -----END PRIVATE KEY-----

However that means this config are unable to commit to github
Is there a way to allow us store the key in somewhere and call the json key

  secureJsonData:
    privateKey: thekey.json

Thanks