update wycheproof-testvectors to HEAD

Trivial update. This way it's easier to be sure we're up-to-date.

No change in the packaged .json files. Surprisingly, the
libcrypto/wycheproof tests still pass.

Index: Makefile
===================================================================
RCS file: /var/cvs/ports/security/wycheproof-testvectors/Makefile,v
retrieving revision 1.2
diff -u -p -r1.2 Makefile
--- Makefile 7 Aug 2018 19:00:05 -0000 1.2
+++ Makefile 28 Sep 2018 13:38:16 -0000
@@ -3,12 +3,12 @@
COMMENT = test vectors from Project Wycheproof

# No releases
-VERSION = 20180731
+VERSION = 20180921
DISTNAME = wycheproof-testvectors-${VERSION}

GH_ACCOUNT = google
GH_PROJECT = wycheproof
-GH_COMMIT = f89f4c53a8845fcefcdb9f14ee9191dbe167e3e3
+GH_COMMIT = c313761979d74b0417230eddd0f87d0cfab2b46b

CATEGORIES = security devel

Index: distinfo
===================================================================
RCS file: /var/cvs/ports/security/wycheproof-testvectors/distinfo,v
retrieving revision 1.2
diff -u -p -r1.2 distinfo
--- distinfo 7 Aug 2018 19:00:05 -0000 1.2
+++ distinfo 28 Sep 2018 13:38:41 -0000
@@ -1,2 +1,2 @@
-SHA256 (wycheproof-testvectors-20180731-f89f4c53.tar.gz) = n7NHmhUKEoCPzxRxZwpBPWQ9ZvqTE6HxwRcrnEwbYvo=
-SIZE (wycheproof-testvectors-20180731-f89f4c53.tar.gz) = 2840019
+SHA256 (wycheproof-testvectors-20180921-c3137619.tar.gz) = JMXMBektFHIhSGgxKt9D/AiMW4C5TzQ1JOO6YmGXiKk=
+SIZE (wycheproof-testvectors-20180921-c3137619.tar.gz) = 2840071