Update the pointer in the DID:sov DID Method to the Sovrin Foundation repo
Update the pointer in the DID:sov DID Method to the Sovrin Foundation repo

Signed-off-by: Stephen Curran <941e58e189f3c1f0cc08828d7f189c0a4fce1702@gmail.com>

sovrin-foundation/sovrin,sovrin-foundation/sovrin,sovrin-foundation/sovrin