Revert Fix encoding of process output under windows (#784)

This appears to break usage under Linux. Until a proper solution can be
implemented, revert.

lib/overcommit/subprocess.rb

@@ -52,7 +52,7 @@ def spawn(args, options = {})
         err.rewind
         out.rewind
 
-        Result.new(process.exit_code, to_utf8(out.read), to_utf8(err.read))
+        Result.new(process.exit_code, out.read, err.read)
       end
 
       # Spawns a new process in the background using the given array of
@@ -84,27 +84,6 @@ def win32_prepare_args(args)
         %w[cmd.exe /c] + [args.join(' ')]
       end
 
-      # Convert string from current locale to utf-8
-      #
-      # When running commands under windows the command output is using
-      # current system locale (depends on system lanuage) not UTF-8
-      #
-      # @param process [String]
-      # @return [String]
-      def to_utf8(string)
-        # Our encoding code doesn't work on the GitHub Actions Windows
-        # environment for unknown reasons, so just skip it in CI.
-        return string if OS.windows? && ENV['GITHUB_ACTIONS']
-
-        if Encoding.locale_charmap == 'UTF-8'
-          return string
-        end
-
-        ec = Encoding::Converter.new(Encoding.locale_charmap, 'UTF-8')
-        # Convert encoding, alternatively simple: string.scrub will suffice
-        ec.convert(string)
-      end
-
       # @param process [ChildProcess]
       # @return [Array<IO>]
       def assign_output_streams(process)