Bump Rinku to 2.0.0

CHANGELOG

@@ -24,6 +24,7 @@ v 8.10.0 (unreleased)
   - PipelinesFinder uses git cache data
   - Check for conflicts with existing Project's wiki path when creating a new project.
   - Don't instantiate a git tree on Projects show default view
+  - Bump Rinku to 2.0.0
   - Remove unused front-end variable -> default_issues_tracker
   - Better caching of git calls on ProjectsController#show.
   - Add API endpoint for a group issues !4520 (mahcsig)

Gemfile.lock

@@ -578,7 +578,7 @@ GEM
       listen (~> 3.0)
     responders (2.1.1)
       railties (>= 4.2.0, < 5.1)
-    rinku (1.7.3)
+    rinku (2.0.0)
     rotp (2.1.2)
     rouge (1.11.0)
     rqrcode (0.7.0)