Bump sprockets from 3.7.2 to 4.0.3

Bumps [sprockets](https://github.com/rails/sprockets) from 3.7.2 to 4.0.3.
- [Release notes](https://github.com/rails/sprockets/releases)
- [Changelog](https://github.com/rails/sprockets/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rails/sprockets/commits)

---
updated-dependencies:
- dependency-name: sprockets
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -13,7 +13,7 @@ source "https://rubygems.org"
 gem "jekyll", "~> 3.8"
 
 # See https://github.com/envygeeks/jekyll-assets/issues/622
-gem "sprockets", "~> 3.7"
+gem "sprockets", "~> 4.0"
 
 # If you have any plugins, put them here!
 group :jekyll_plugins do

Gemfile.lock

@@ -9,7 +9,7 @@ GEM
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    concurrent-ruby (1.1.6)
+    concurrent-ruby (1.1.10)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
@@ -96,7 +96,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.4)
-    rack (2.0.8)
+    rack (2.2.3)
     rainbow (3.0.0)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.1)
@@ -108,7 +108,7 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    sprockets (3.7.2)
+    sprockets (4.0.3)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     thread_safe (0.3.6)
@@ -118,7 +118,6 @@ GEM
       thread_safe (~> 0.1)
     tzinfo-data (1.2020.1)
       tzinfo (>= 1.0.0)
-    wdm (0.1.1)
     yell (2.2.2)
 
 PLATFORMS
@@ -134,9 +133,8 @@ DEPENDENCIES
   jekyll-redirect-from
   jekyll-seo-tag
   jekyll-sitemap
-  sprockets (~> 3.7)
+  sprockets (~> 4.0)
   tzinfo-data
-  wdm (~> 0.1.0)
 
 RUBY VERSION
    ruby 2.6.3p62