cctbx builder clones branch dials-3.5 of dxtbx which is incompatible with Python >= 3.12

[luc-j-bourhis]

This happened with:

/usr/bin/python bootstrap.py --python 312  --builder=cctbx --nproc=10 --use-conda --no-boost-src

libtbx_refresh.py in that branch imports the imp module which was removed in Python 3.12. This has been fixed years ago on dxtbx master.

[bkpoon]

I bumped up the version to 3.22 (430715e). The CI is currently checking that version out in a different step. Do you have another version in mind?

[luc-j-bourhis]

3.22 should be fine indeed but the CI failed because of clutter in an unrelated file unfortunately!