Update py-freezegun to 0.3.12. This version fixes incompatibilities
with Python 3.7.x fixing tests for any python3 ports using it.
OK jung@ (maintainer) sthen@
lang/python port module. I've not yet come up with a port that
would not need this and one can always set MODPY_TESTDEP to "no"
to prevent the module from touching TEST_DEPENDS.
Idea from afresh1 who pointed out the cpan module already does this.
aja "I support this move."
OK sthen@
