[Security] Bump sprockets from 3.7.1 to 3.7.2

Bumps [sprockets](http://getsprockets.org/) from 3.7.1 to 3.7.2. **This update includes security fixes.**

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

Gemfile.lock

@@ -230,7 +230,7 @@ GEM
       pry (~> 0.10)
     public_suffix (3.0.1)
     puma (3.11.2)
-    rack (1.6.8)
+    rack (1.6.10)
     rack-cors (1.0.2)
     rack-protection (2.0.0)
       rack
@@ -372,7 +372,7 @@ GEM
       actionpack (>= 3.1)
       railties (>= 3.1)
       slim (~> 3.0)
-    sprockets (3.7.1)
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (2.3.3)