add python verson

Author: imallona

.github/workflows/micromamba.yml

@@ -33,13 +33,17 @@ jobs:
       - name: Install (with) micromamba
         uses: mamba-org/setup-micromamba@v2
         with:
-          # cache-environment: true
+          cache-environment: true
           micromamba-version: ${{ matrix.micromamba_version }}
-
+          environment-name: test-env
+          create-args: >-
+            python=3.12
+            pip
+            mamba
+      
       - name: Overwrite omnibenchmark CLI to branch
         shell: bash -l {0}
         run: |
-          mamba install -y pip
           pip install git+https://github.com/omnibenchmark/omnibenchmark.git@${{ matrix.ob_branch }}
 
       # - name: Enable a benchmarking `out` cache