net-mgmt/aicrack-ng:

• Set required GCC version to 6+, so that the default gcc version is chosen.

GCC isn't needed to successfully building the port, but according to upstream
using the gcc compiled version is 60-70% faster than the clang compiled
version.

• Bump PORTREVISION

PR: 228747
Submitted by: Michael Danilov <mike.d.ft402@gmail.com>