Revert "fix gem with unsupported nodejs version"

This reverts commit f3b8a99f.

Gemfile

@@ -5,8 +5,6 @@ ruby '~> 2.5'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.0'
-# nodejs version too old on EL7, TODO: remove once migrated
-gem 'autoprefixer-rails', '~> 9.7.6'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.3', '< 1.4'
 # Use Puma as the app server

Gemfile.lock

@@ -48,7 +48,7 @@ GEM
       io-like (~> 0.3.0)
     arel (9.0.0)
     ast (2.4.1)
-    autoprefixer-rails (9.7.6)
+    autoprefixer-rails (10.0.0.2)
       execjs
     base32 (0.3.4)
     bindex (0.8.1)
@@ -266,7 +266,6 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  autoprefixer-rails (~> 9.7.6)
   base32
   bootstrap (~> 4.4.1)
   byebug