Add GPG signing to Github bootstrap

Signed-off-by: Robert Wittman <robkwittman@gmail.com>

cmd/flux/bootstrap_github.go

@@ -243,6 +243,7 @@ func bootstrapGitHubCmdRun(cmd *cobra.Command, args []string) error {
 		bootstrap.WithKubeconfig(kubeconfigArgs),
 		bootstrap.WithLogger(logger),
 		bootstrap.WithCABundle(caBundle),
+		bootstrap.WithGitCommitSigning(bootstrapArgs.gpgKeyRingPath, bootstrapArgs.gpgPassphrase, bootstrapArgs.gpgKeyID),
 	}
 	if bootstrapArgs.sshHostname != "" {
 		bootstrapOpts = append(bootstrapOpts, bootstrap.WithSSHHostname(bootstrapArgs.sshHostname))