Update the gitlab-markup gem to the version `1.5.1`

Gemfile

@@ -101,7 +101,7 @@ gem 'seed-fu', '~> 2.3.5'
 # Markdown and HTML processing
 gem 'html-pipeline',      '~> 1.11.0'
 gem 'deckar01-task_list', '1.0.6', require: 'task_list/railtie'
-gem 'gitlab-markup',      '~> 1.5.0'
+gem 'gitlab-markup',      '~> 1.5.1'
 gem 'redcarpet',          '~> 3.3.3'
 gem 'RedCloth',           '~> 4.3.2'
 gem 'rdoc',               '~> 4.2'

Gemfile.lock

@@ -263,7 +263,7 @@ GEM
       diff-lcs (~> 1.1)
       mime-types (>= 1.16, < 3)
       posix-spawn (~> 0.3)
-    gitlab-markup (1.5.0)
+    gitlab-markup (1.5.1)
     gitlab_omniauth-ldap (1.2.1)
       net-ldap (~> 0.9)
       omniauth (~> 1.0)
@@ -892,7 +892,7 @@ DEPENDENCIES
   gemojione (~> 3.0)
   github-linguist (~> 4.7.0)
   gitlab-flowdock-git-hook (~> 1.0.1)
-  gitlab-markup (~> 1.5.0)
+  gitlab-markup (~> 1.5.1)
   gitlab_omniauth-ldap (~> 1.2.1)
   gollum-lib (~> 4.2)
   gollum-rugged_adapter (~> 0.4.2)