Bump version to force upgrade during pip install docopt - #529

Current version on PyPi is 0.6.2 but the source code in this file is not what is installed.  For example the following Python re SyntaxWarnings are generated when non-raw strings are passed to `re` when pymux installs and uses the latest version on pypi.org:

```bash
/home/hobs/code/public-by-others/pymux/.venv/lib/python3.12/site-packages/docopt.py:165: SyntaxWarning: invalid escape sequence '\S'
  name = re.findall('(<\S*?>)', source)[0]
/home/hobs/code/public-by-others/pymux/.venv/lib/python3.12/site-packages/docopt.py:166: SyntaxWarning: invalid escape sequence '\['
  value = re.findall('\[default: (.*)\]', source, flags=re.I)
/home/hobs/code/public-by-others/pymux/.venv/lib/python3.12/site-packages/docopt.py:207: SyntaxWarning: invalid escape sequence '\['
  matched = re.findall('\[default: (.*)\]', description, flags=re.I)
/home/hobs/code/public-by-others/pymux/.venv/lib/python3.12/site-packages/docopt.py:456: SyntaxWarning: invalid escape sequence '\S'
  split = re.split('\n *(<\S+?>|-\S+?)', doc)[1:]
```