dependency on 'safe_filename' from 'bw_processing' causes import error

[PascalLesage]

I'm trying to contribute to bw2io (add SimaPro 3.4 and 3.5 mappings).
I followed the following steps:

• forked from https://github.com/brightway-lca/brightway2-io.git
• created a conda environment and installed brightway2 as per https://2.docs.brightway.dev/installation.html
• I pip install -e brightway2-io 

All this seems to work as normal, but unfortunately, a May 26 commit has added a dependency to bw_processing and is preventing me from importing bw2io.

[PascalLesage]

Of course, the obvious workaround (that works well) is to clone and install the latest version of bw_processing.

[PascalLesage]

And while the fix works on one's computer, automatic testing on github fails when submitting a PR.

[cmutel]

Fixed. 0.8 release is on the legacy branch, with no bw_processing dependency, while bw_processing is explicitly a dependency on development branch.