Update cibuild

MartiUK · web-flow · commit 08e15d676303 · 2016-09-28T12:21:16.000+01:00
htmlproof binary is htmlproofer now.
diff --git a/script/cibuild b/script/cibuild
@@ -2,4 +2,4 @@
 set -e # halt script on error
 
 bundle exec jekyll build
-bundle exec htmlproof ./_site
+bundle exec htmlproofer ./_site
