for another problem I had I was upgrading my Slicer install to the nightly build version. Unfortunately I have problems running the pip installer in the Python Interactive console. I am running the nightly version on a windows system and get the following error:
pip.main was removed in newer versions of pip. For interactive/one-shot use you can run it from the command line in a Slicer-aware shell (look at Slicer --launcher-show-set-environment-commands); for dependency installation as part of a module build, you can shell out from your CMake build.
I think Slicer --launch already prefers binaries in Slicer’s PATH, so the other option is to document pip as Slicer --launch pip (only a few more characters).