Try pinning v2.0.0-0

.github/workflows/linux_conda.yml

@@ -32,6 +32,7 @@ jobs:
           pyvista: false
       - uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '2.0.0-0'
           environment-file: environment.yml
           create-args: >- # beware the >- instead of |, we don't split on newlines but on spaces
             python=${{ env.PYTHON_VERSION }}