Failing Conda builds of LALSuite

Summary

Looking for: ['conda', "mamba[version='<0.18.0']"]
Pinned packages:
  - python 3.9.*
Encountered problems while solving:
  - package mamba-0.1.2-py38hbf85e49_0 requires python >=3.8,<3.9.0a0, but none of the providers can be installed
igwn/linux-64             
igwn/noarch               
The command has failed after 3 attempts.

https://git.ligo.org/ANU-CGA/lalsuite/-/jobs/1690519 https://git.ligo.org/ANU-CGA/lalsuite/-/jobs/1690520

cc @duncanmmacleod @adam-mercer

Steps to reproduce

Run a LALSuite CI job

Context/environment

Hostname: git.ligo.org