one more config fix for CI

.github/workflows/python-ci.yaml

@@ -12,10 +12,10 @@ jobs:
 
     strategy:
       matrix:
-        python-version: [3.10, 3.11]
+        python-version: ["3.10", "3.11"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install Micromamba
         run: |
@@ -26,7 +26,12 @@ jobs:
       - name: Create environment
         run: |
           micromamba create --name test-env -f environment.yaml -y -c conda-forge
-          echo "micromamba activate test-env" >> $GITHUB_ENV
+        env:
+          MAMBA_ROOT_PREFIX: /usr/local/micromamba
+
+      - name: Set up Micromamba environment
+        run: echo "MICROMAMBA_ROOT_PREFIX=/usr/local/micromamba" >> $GITHUB_ENV
+        shell: bash
 
       - name: Install dependencies
         run: micromamba run -n test-env micromamba install -y -f environment.yaml -c conda-forge