Bump simplecov from 0.16.1 to 0.21.2

Gemfile

@@ -45,7 +45,7 @@ gem 'redis-namespace'
 gem 'sass-rails', '~> 5.0'
 gem 'secure_headers', '~> 3.9'
 gem 'sidekiq', '>= 6.2.0'
-gem 'simplecov', '0.16.1'
+gem 'simplecov', '0.21.2'
 gem 'slack-notifier'
 
 gem 'tinymce-rails', '>= 4.9.2'

Gemfile.lock

@@ -528,11 +528,12 @@ GEM
       rack (~> 2.0)
       redis (>= 4.2.0)
     simple_po_parser (1.1.6)
-    simplecov (0.16.1)
+    simplecov (0.21.2)
       docile (~> 1.1)
-      json (>= 1.8, < 3)
-      simplecov-html (~> 0.10.0)
-    simplecov-html (0.10.2)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
     sitemap_generator (6.2.1)
       builder (~> 3.0)
     sixarm_ruby_unaccent (1.2.0)
@@ -660,7 +661,7 @@ DEPENDENCIES
   selenium-webdriver
   shoulda-matchers
   sidekiq (>= 6.2.0)
-  simplecov (= 0.16.1)
+  simplecov (= 0.21.2)
   sitemap_generator
   slack-notifier
   spring