Linting issues

[jrs65]

Two related issues:

First, running the caput-pipeline lint command breaks with a venv config key. It seems to be confused about whether it's dealing with a string or Path object

caput-pipeline lint qs_singledays.yaml
Activating '/home/jrs65/chime_pipeline/venv/'...
Traceback (most recent call last):
  File "/home/jrs65/chime_pipeline/venv/bin/caput-pipeline", line 11, in <module>
    load_entry_point('caput', 'console_scripts', 'caput-pipeline')()
  File "/home/jrs65/chime_pipeline/venv/lib/python3.8/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/home/jrs65/chime_pipeline/venv/lib/python3.8/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/home/jrs65/chime_pipeline/venv/lib/python3.8/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/jrs65/chime_pipeline/venv/lib/python3.8/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/jrs65/chime_pipeline/venv/lib/python3.8/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/home/jrs65/chime_pipeline/code/caput/caput/scripts/runner.py", line 44, in lint_config
    load_venv(f)
  File "/home/jrs65/chime_pipeline/code/caput/caput/scripts/runner.py", line 75, in load_venv
    if not base.exists():
AttributeError: 'str' object has no attribute 'exists'

Second, the queue command despite "linting" the file before submitting doesn't break with this because it doesn't run the linter within in the venv.