code: func ExampleSigningConfig() *config.Signing {
  	return &config.Signing{
  		Default: &config.SigningProfile{
  			Expiry: 15 * time.Minute,
  			Usage: []string{
  				"server auth", "client auth",
  				"signing", "key encipherment",
  			},
  		},
  	}
  }
docs: // ExampleSigningConfig returns a sample config.Signing with only a
  // default profile.