Update segwitsupport.csv

Author: SimpleFX

_data/segwitsupport.csv

@@ -135,3 +135,4 @@ KeeeX,https://keeex.me,ready,"notarization and document proofs",
 CryptoBG,https://crypto.bg/,ready,exchange,
 bitcoin-ruby,https://github.com/lian/bitcoin-ruby,ready,library,n/a
 BitBay,https://bitbay.net/,wip,exchange,
+SimpleFX,https://simplefx.com,ready,"broker, financial services","bitcoin core"