bug: conda and mamba are not 100% exchangeable

[kemingy]

Description

• we supported micromamba in feat: support micromamba as an alternative to miniconda #891

Currently, we cannot replace miniconda with micromamba because:

• their command-line interfaces are not exactly the same
  • micromamba create -n envd python=3.7 --file env.yaml v.s. conda env create -n envd python=3.7 --file env.yaml
  • micromamba update -n envd --file env.yaml v.s. conda env update -n envd --file env.yaml
  • micromamba update --file env.yaml won't install new packages from the YAML file

Additional Info

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[kemingy]

According to my observation, micromamba update -f env.yaml doesn't install anything from the YAML file. Instead, it only updates all the existing packages.

We'd better use conda update because it requires mounts, which means it cannot be cached.

Originally posted by @kemingy in #933 (comment)