fix: add heroku wkhtmltopdf gem comments as reminder when switching

Gemfile

@@ -57,10 +57,12 @@ gem 'webpacker'
 gem 'wicked_pdf'
 gem 'will_paginate'
 gem 'will-paginate-i18n'
+gem 'wkhtmltopdf-binary' # When switching to Heroku remove this gem here
 
-group :production do
-  gem 'wkhtmltopdf-heroku'
-end
+## When switching to Heroku uncomment this group here
+# group :production do
+#   gem 'wkhtmltopdf-heroku'
+# end
 
 group :development do
   gem 'debase', require: false
@@ -89,7 +91,8 @@ group :development, :test do
   gem 'pry-byebug'
   gem 'pry-stack_explorer'
   gem 'spring'
-  gem 'wkhtmltopdf-binary'
+  ## When switching to Heroku uncomment this gem here
+  # gem 'wkhtmltopdf-binary'
 end
 
 group :test do

Gemfile.lock

@@ -543,7 +543,6 @@ GEM
     will-paginate-i18n (0.1.15)
     will_paginate (3.3.0)
     wkhtmltopdf-binary (0.12.5.4)
-    wkhtmltopdf-heroku (2.12.6.0)
     xpath (3.2.0)
       nokogiri (~> 1.8)
     zeitwerk (2.4.2)
@@ -635,7 +634,6 @@ DEPENDENCIES
   will-paginate-i18n
   will_paginate
   wkhtmltopdf-binary
-  wkhtmltopdf-heroku
 
 RUBY VERSION
    ruby 2.6.6p146