Bump tzinfo-data from 1.2018.3 to 1.2018.4

Bumps [tzinfo-data](https://github.com/tzinfo/tzinfo-data) from 1.2018.3 to 1.2018.4.
- [Release notes](https://github.com/tzinfo/tzinfo-data/releases)
- [Commits](tzinfo/tzinfo-data@v1.2018.3...v1.2018.4)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Gemfile.lock

@@ -360,7 +360,7 @@ GEM
     turbolinks-source (5.1.0)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    tzinfo-data (1.2018.3)
+    tzinfo-data (1.2018.4)
       tzinfo (>= 1.0.0)
     unicode-display_width (1.3.0)
     uniform_notifier (1.11.0)