Remove iconv conditional require

Drop legacy character encoding support for Ruby versions  prior to 1.9,
as string encoding is now natively supported in modern Ruby versions.

Author: tagliala

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Unreleased
 
+* Remove `iconv` conditional require
+
 ### Version v1.19.1
 
 * Fix error when parsing values consisting of `!important` only

lib/css_parser.rb

@@ -6,7 +6,6 @@
 require 'digest/md5'
 require 'zlib'
 require 'stringio'
-require 'iconv' unless String.method_defined?(:encode)
 
 require 'css_parser/version'
 require 'css_parser/rule_set'

lib/css_parser/parser.rb

@@ -677,12 +677,7 @@ def read_remote_file(uri) # :nodoc:
         end
 
         if charset
-          if String.method_defined?(:encode)
-            src.encode!('UTF-8', charset)
-          else
-            ic = Iconv.new('UTF-8//IGNORE', charset)
-            src = ic.iconv(src)
-          end
+          src.encode!('UTF-8', charset)
         end
       rescue
         @redirect_count = nil