Add recurse submodules arg to create source git cmd

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

docs/cmd/flux_create_source_git.md

@@ -70,6 +70,7 @@ flux create source git [name] [flags]
   -h, --help                                   help for git
   -p, --password string                        basic authentication password
       --private-key-file string                path to a passwordless private key file used for authenticating to the Git SSH server
+      --recurse-submodules                     when enabled, after the clone is created, initializes all Git submodules within
       --secret-ref string                      the name of an existing secret containing SSH or basic credentials
       --ssh-ecdsa-curve ecdsaCurve             SSH ECDSA public key curve (p256, p384, p521) (default p384)
       --ssh-key-algorithm publicKeyAlgorithm   SSH public key algorithm (rsa, ecdsa, ed25519) (default rsa)