Specifies which credential to use in order to connect to Google Play.
The selected credential must be a "Google Service Account from private
key" — if you have not added one already, refer to the documentation
on this
plugin's page.
By choosing the "Parameter expression" option, you can also provide a
credential at build time, either from an environment variable, or from
a build parameter, e.g. the Credentials Parameter type.
But you can use any type of expression, so long as it expands to the
name of a "Google Service Account from private key" credential at
build time.
This field supports substituting environment variables in the form
${SOME_VARIABLE} at build time.
Note that variables in the form $SOME_VARIABLE are
not accepted by the Credentials Plugin.