Update config.py

Author: ivankravets

platformio/project/config.py

@@ -102,7 +102,7 @@ def read(self, path, parse_extra=True):
  return
  self._parsed.append(path)
  try:
- self._parser.read(path, 'UTF-8')
+ self._parser.read(path, "utf-8")
  except ConfigParser.Error as e:
  raise exception.InvalidProjectConfError(path, str(e))