Bump uglifier from 3.2.0 to 4.1.8

Bumps [uglifier](https://github.com/lautis/uglifier) from 3.2.0 to 4.1.8.
- [Release notes](https://github.com/lautis/uglifier/releases)
- [Changelog](https://github.com/lautis/uglifier/blob/master/CHANGELOG.md)
- [Commits](lautis/uglifier@v3.2.0...v4.1.8)

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

Gemfile

@@ -43,7 +43,7 @@ gem 'nokogiri', '1.8.2'
 
 # See https://github.com/sstephenson/execjs#readme for more supported runtimes
 gem 'therubyracer', '~> 0.12.3', :platforms => :ruby
-gem 'uglifier', '~> 3.2.0'
+gem 'uglifier', '~> 4.1.8'
 gem 'rspec-mocks', '3.6.0'
 gem 'newrelic_rpm', '4.1.0.333'
 

Gemfile.lock

@@ -139,7 +139,7 @@ GEM
     equivalent-xml (0.6.0)
       nokogiri (>= 1.4.3)
     erubis (2.7.0)
-    execjs (2.6.0)
+    execjs (2.7.0)
     faraday (0.12.1)
       multipart-post (>= 1.2, < 3)
     fastercsv (1.5.5)
@@ -412,7 +412,7 @@ GEM
     tzinfo (1.2.3)
       thread_safe (~> 0.1)
     uber (0.0.15)
-    uglifier (3.2.0)
+    uglifier (4.1.8)
       execjs (>= 0.3.0, < 3)
     unf (0.1.4)
       unf_ext
@@ -488,7 +488,7 @@ DEPENDENCIES
   sprockets (~> 2.12.4)
   sqlite3 (~> 1.3.13)
   therubyracer (~> 0.12.3)
-  uglifier (~> 3.2.0)
+  uglifier (~> 4.1.8)
   unicode (= 0.4.4.3)
   unicorn (~> 5.3.0)