codes.open is deprecated in python3.14

Depreciation warning in python3:

```
<omitted>/lib/python3.14/site-packages/publicsuffix2/__init__.py:86: DeprecationWarning: codecs.open() is deprecated. Use open() instead.
  with codecs.open(psl_file or PSL_FILE, 'r', encoding='utf8') as psl:
```