Compatibility with coverage plugins

[mgedmin]

We're trying to use this action for a project that uses coverage.py plugins (specifically, https://pypi.org/project/coverage-python-version/), and we're experiencing the following problem:

https://github.com/zopefoundation/zope.interface/pull/243/checks?check_run_id=2515733925

Trying submitting coverage with service_name: github...
cd .
cd /github/workspace
No module named 'coverage_python_version'
Traceback (most recent call last):
  File "/src/entrypoint.py", line 176, in try_main
    main()
  File "/src/entrypoint.py", line 171, in main
    run_coveralls(repo_token, parallel, flag_name, base_path)
  File "/src/entrypoint.py", line 82, in run_coveralls
    result = coveralls.wear()
  File "/usr/local/lib/python3.9/site-packages/coveralls/api.py", line 223, in wear
    json_string = self.create_report()
  File "/usr/local/lib/python3.9/site-packages/coveralls/api.py", line 299, in create_report
    data = self.create_data()
  File "/usr/local/lib/python3.9/site-packages/coveralls/api.py", line 353, in create_data
    self._data = {'source_files': self.get_coverage()}
  File "/usr/local/lib/python3.9/site-packages/coveralls/api.py", line 368, in get_coverage
    workman.load()
  File "/usr/local/lib/python3.9/site-packages/coverage/control.py", line 418, in load
    self._init()
  File "/usr/local/lib/python3.9/site-packages/coverage/control.py", line 275, in _init
    self._plugins = Plugins.load_plugins(self.config.plugins, self.config, self._debug)
  File "/usr/local/lib/python3.9/site-packages/coverage/plugin_support.py", line 41, in load_plugins
    __import__(module)
ModuleNotFoundError: No module named 'coverage_python_version'
ExitCode.FAILURE

Perhaps it would be possible to add a configuration option for people to specify a list of pip packages to pip install inside the Docker container before invoking coveralls?