[ruby/rubygems] Lock diff-lcs < 2.0

ruby/rubygems@23aecf4a86

Author: hsbt

spec/bundler/spec_helper.rb

@@ -21,7 +21,7 @@
 
 # If we use shared GEM_HOME and install multiple versions, it may cause
 # unexpected test failures.
-gem "diff-lcs"
+gem "diff-lcs", "< 2.0"
 
 require "rspec/core"
 require "rspec/expectations"