Bump uglifier from 3.2.0 to 4.1.20

Bumps [uglifier](https://github.com/lautis/uglifier) from 3.2.0 to 4.1.20.
- [Release notes](https://github.com/lautis/uglifier/releases)
- [Changelog](https://github.com/lautis/uglifier/blob/master/CHANGELOG.md)
- [Commits](lautis/uglifier@v3.2.0...v4.1.20)

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

Gemfile

@@ -41,7 +41,7 @@ gem "bower-rails", "~> 0.11.0"
 gem "responders", "~> 2.4.0"
 gem 'nokogiri', '1.10.3'
 
-gem 'uglifier', '~> 3.2.0'
+gem 'uglifier', '~> 4.1.20'
 gem 'rspec-mocks', '3.6.0'
 
 gem 'honeycomb-beeline'

Gemfile.lock

@@ -153,7 +153,7 @@ 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)
     faraday-honeycomb (0.3.3)
@@ -441,7 +441,7 @@ GEM
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
     uber (0.0.15)
-    uglifier (3.2.0)
+    uglifier (4.1.20)
       execjs (>= 0.3.0, < 3)
     unf (0.1.4)
       unf_ext
@@ -520,7 +520,7 @@ DEPENDENCIES
   solrizer-fedora!
   sprockets (~> 2.12.4)
   timecop
-  uglifier (~> 3.2.0)
+  uglifier (~> 4.1.20)
   unicorn (~> 5.3.0)
   whenever