DOC: use conda-forge in Ubuntu quickstart

[fuglede]

Without this, none of pythran, sphinx-panels, or pydata-sphinx-theme can be found. The phrasing is taken from the corresponding point in the macOS workflow.

Reference issue

Closes gh-14654.

[tupui]

LGTM, thanks!

[mdhaber]

@fuglede @tupui just curious - did you try out the conda-forge compilers? Just checking because in the past not all compilers have been interchangeable, and I don't have easy access to a Linux machine right now to try

[fuglede]

@fuglede @tupui just curious - did you try out the conda-forge compilers? Just checking because in the past not all compilers have been interchangeable, and I don't have easy access to a Linux machine right now to try

Yep, I was able to successfully build after getting all those packages with -c conda-forge in an otherwise empty conda environment, but I have a bunch of compilers on the OS level as well, and I didn't check if that helped me somehow. But in particular, I did also just use -c conda-forge (where, IIRC, with --add channels conda-forge, packages are still picked up from defaults with higher solver priority?) so my setup wouldn't be one-to-one what these docs give you.

It was also the only way I was able to get it building (without relying on Docker) where until a few months ago I could just build inplace with my OS compilers, avoid conda develop . and all of that, so although I can appreciate the reproducibility that this workflow offers, it did seem like a step backwards UX-wise for my own workflow.