unstructured

9a9bf4c4 - Added contributing from archived repo (#3616)

Added contributing from archived repo (#3616) Added `CONTRIBUTING.md` from the archived repo as mentioned in the issue: https://github.com/Unstructured-IO/unstructured/issues/3540 Co-authored-by: John <43506685+Coniferish@users.noreply.github.com>