Revert "Let it pull down 2.0.1?"

This reverts commit 3a19553.

.github/workflows/full-stack.yaml

@@ -75,6 +75,7 @@ jobs:
     - name: Set up conda environment
       uses: mamba-org/setup-micromamba@v1
       with:
+        micromamba-version: '1.5.10-0'  # maybe fixed with 2.0.1-0
         environment-file: devtools/conda-envs/full-stack.yaml
         create-args: python=${{ matrix.python-version }}