Privacy plugin is missing lxml as dependency

[Guts]

Contribution guidelines

• I've read the contribution guidelines and wholeheartedly agree

I've found a bug and checked that ...

• ... the problem doesn't occur with the mkdocs or readthedocs themes
• ... the problem persists when all overrides are removed, i.e. custom_dir, extra_javascript and extra_css
• ... the documentation does not mention anything about my problem
• ... there are no open or closed issues that are related to my problem

Description

The new Privacy plugin is missing lxml package as dependency in setup.py/pyproject.toml.

Expected behaviour

Build works

Actual behaviour

❯ mkdocs build
Traceback (most recent call last):
  File "/home/username/Git/Geotribu/website/.venv/bin/mkdocs", line 8, in <module>
    sys.exit(cli())
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/__main__.py", line 187, in build_command
    build.build(config.load_config(**kwargs), dirty=not clean)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/base.py", line 224, in load_config
    errors, warnings = cfg.validate()
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/base.py", line 108, in validate
    run_failed, run_warnings = self._validate()
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/base.py", line 63, in _validate
    self[key] = config_option.validate(value)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/config_options.py", line 130, in validate
    return self.run_validation(value)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/config_options.py", line 636, in run_validation
    plgins[item] = self.load_plugin(item, cfg)
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/mkdocs/config/config_options.py", line 649, in load_plugin
    Plugin = self.installed_plugins[name].load()
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/importlib_metadata/__init__.py", line 194, in load
    module = import_module(match.group('module'))
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 848, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/username/Git/Geotribu/website/.venv/lib/python3.8/site-packages/material/plugins/privacy/plugin.py", line 25, in <module>
    from lxml import html
ModuleNotFoundError: No module named 'lxml'

Steps to reproduce

1. Install Insiders: python -m pip install -U git+https://${GH_TOKEN_MATERIAL_INSIDERS}@github.com/squidfunk/mkdocs-material-insiders.git@8.2.1-insiders-4.9.0#egg=mkdocs-material
2. Enable Privacy plugin according to https://squidfunk.github.io/mkdocs-material/setup/ensuring-data-privacy/#built-in-privacy
3. mkdocs build

Package versions

• Python: 3.8
• MkDocs: 1.2.3
• Material: 8.2.1+insiders.4.9.0

Configuration

- plugins:
    -privacy:
        download: !ENV [MATERIAL_PRIVACY_PLUGIN, true]

System information

Ubuntu LTS (20.04)

[squidfunk]

Already fixed 😊 @wilhelmer already reached out to me. I'll issue a new release shortly.

[squidfunk]

Released as part of 8.2.1+insiders-4.9.1