CI: Remove conda-forge::libmambapy

Author: oyamad

.github/workflows/ci_np2.yml

@@ -24,7 +24,7 @@ jobs:
         echo $CONDA/bin >> $GITHUB_PATH
     - name: Install dependencies
       run: |
-        conda install conda-forge::libmamba conda-forge::libmambapy conda-forge::libarchive
+        conda install conda-forge::libmamba conda-forge::libarchive
         conda install -c numba numba=0.61.0rc1
         conda env update --file environment_np2.yml --name base
     - name: Conda info