security/obfs4proxy-tor: update WWW on port's pkg-descr

Reported by:	grahamperrin % gmail.com
PR:		257048

security/obfs4proxy-tor/pkg-descr

@@ -2,4 +2,4 @@ obfs4 (a.k.a. The Obfuscator) is a transport with the same features as
 ScrambleSuit but utilizing Dan Bernstein's elligator2 technique for public
 key obfuscation, and the ntor protocol for one-way authentication.
 
-WWW: https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports/obfs4proxy
+WWW: https://gitlab.com/yawning/obfs4