upgrade bibtex-ruby

jekyll-scholar.gemspec

@@ -26,7 +26,7 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency('jekyll', '~> 0.10')
   s.add_runtime_dependency('citeproc-ruby', '~> 0.0.6')
-  s.add_runtime_dependency('bibtex-ruby', '~> 2.2')
+  s.add_runtime_dependency('bibtex-ruby', '~> 2.3')
 
   s.files        = `git ls-files`.split("\n")
   s.test_files   = `git ls-files -- {test,spec,features}/*`.split("\n")