Updated conda environment; bugfixes, fastavro added [RFC-693]

The conda environment from last week, announced here, has been updated again.

We encountered a few issues which were not discovered in CI:

  • On Catalina with python 3.7, matplotlib 3.1+ is broken with code that uses multiprocessing when matplotlib is imported before forking - this happens in fgcmcal. We have downgraded matplotlib to 3.0.3.
  • mpich has a bug with parsing SLURM nodelists. A fix is in master but unreleased. A downgrade has fixed this.
  • fastavro version 0.23.3 has been added to aid in implementing RFC-693