Remove mamba

Author: jorgensd

.github/actions/install-dependencies/action.yml

@@ -41,6 +41,7 @@ runs:
 
     - name: Update environment
       if: steps.cache-env.outputs.cache-hit != 'true'
+      # Change to mamba if we want to use it
       run:
-          mamba env update -n mpi-tutorial -f environment.yml
+          conda env update -n mpi-tutorial -f environment.yml
       shell: bash -el {0}