[UPDATE] textproc/ruby-kramdown to 1.17.0

Hi ports@,

Here is a diff to update ruby-kramdown to 1.17.0.

Comments? OK?

Index: Makefile
===================================================================
RCS file: /cvs/ports/textproc/ruby-kramdown/Makefile,v
retrieving revision 1.8
diff -u -p -r1.8 Makefile
--- Makefile 5 Apr 2018 08:11:18 -0000 1.8
+++ Makefile 30 Jul 2018 15:57:27 -0000
@@ -2,7 +2,7 @@

COMMENT= fast, pure Ruby Markdown parser

-DISTNAME= kramdown-1.16.2
+DISTNAME= kramdown-1.17.0

CATEGORIES= textproc

Index: distinfo
===================================================================
RCS file: /cvs/ports/textproc/ruby-kramdown/distinfo,v
retrieving revision 1.4
diff -u -p -r1.4 distinfo
--- distinfo 5 Apr 2018 08:11:18 -0000 1.4
+++ distinfo 30 Jul 2018 15:57:27 -0000
@@ -1,2 +1,2 @@
-SHA256 (kramdown-1.16.2.gem) = 6g/+Sy4oaLl2C0qi9za4TlXsf5Sac9PzsC7nAO7FeVY=
-SIZE (kramdown-1.16.2.gem) = 258048
+SHA256 (kramdown-1.17.0.gem) = WGJBCiwWkv3i/MhteNImV3fCK9EB8Rx2RC8WmKskLNg=
+SIZE (kramdown-1.17.0.gem) = 260608