DeprecationWarning in noeval_parser on Python 3.10

I'm seeing this warning on Python 3.10:

```
  .../lib/python3.10/site-packages/bap/noeval_parser.py:124: DeprecationWarning: invalid escape sequence '\.'
    parent = objs[k] = (in_s[i+1:endpos]).encode('utf-8').decode('unicode_escape')
```