[BUG] myst_parser : No module named 'attr'

[Fabien-GELUS]

Describe the bug

Exception occurred:
  File "/Users/fgelus/.virtualenvs/substra-doc-3.8/lib/python3.8/site-packages/myst_parser/main.py", line 3, in <module>
    import attr
ModuleNotFoundError: No module named 'attr'

How To Reproduce

• Create a python 3.8.2 clean venv
• follow the readme (install substra libs and requirements.txt)
• run make clean html

Expected behavior

Give a clear and concise description of what you expected to happen.

Screenshots

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Environment

• Version, branch (branch and commit number) https://github.com/Substra/substra-documentation/commit/cf51e6836ab4a465418bb2b93183b80c1c972ae9
• OS and version: [e.g. macOS Mojave version 10.14.4] MacOS monterey

Get it with uname -a on Linux and system_profiler SPSoftwareDataType on Mac

• Browser and version if relevant [e.g. Firefox, Chrome, Safari]
• Any other relevant information [e.g. dependencies, version of Python, version of Go, ...]

Additional context

[Fabien-GELUS]

Solution 1: pip install attrs

But the best would be to upgrade myst-parser to the latest version, and apply the breaking changes: https://myst-parser.readthedocs.io/en/latest/develop/_changelog.html#markdown-link-resolution-improvements