code: func AsReadOnlyCredentials(ctx *AssertContext) {
  	conf := ctx.Config
  	Expect(conf).ToNot(BeNil(),
  		"cannot set read-only AssertContext without config")
  
  	conf.CredentialsSource = config.NoneCredentialsSource
  	conf.ServiceAccountFile = ""
  }
docs: // AsReadOnlyCredentials configures the AssertContext to be used soley for
  // public, read-only operations.