dwave install broken on py39 after utils refactor

[randomir]

Due to a change in entry_points() behavior across a few versions of python (see compatibility note in docs), we use entry_points() from importlib_metadata backport, instead of importlib.metadata.

However, during utils refactor in #628, we switched to importlib.metadata. This causes failure of get_contrib_config (used from dwave install and dwave setup CLI commands) on Python 3.9 (only!).

dwave-cloud-client/dwave/cloud/utils/dist.py

Line 36 in 30d6949

contrib = [ep.load() for ep in entry_points(group='dwave_contrib')]