Restrict w3c_validators to less than 1.3

This is because rdoc 3.10 has a dependency on json ~> 1.4 and
w3c_validators 1.3.0 requires json ~> 2.0.

1 files changed, 1 insertions, 1 deletions

diff --git a/Gemfile b/Gemfile
index 73fdc6c42e..41a10f6f77 100644
--- a/Gemfile
+++ b/Gemfile
@@ -55,7 +55,7 @@ group :doc do
   # this is our own fork with the fix.
   gem 'sdoc',  :git => 'https://github.com/fxn/sdoc.git'
   gem 'RedCloth', '~> 4.2'
-  gem 'w3c_validators'
+  gem 'w3c_validators', '< 1.3'
 end
 
 # AS