Reapply "add conda init before conda activate"

This reverts commit 17a0296.

action.yml

@@ -36,6 +36,7 @@ runs:
     #    shell: bash
   - name: Setup conda env
     run: |
+      $CONDA/bin/conda init
       $CONDA/bin/conda env create -n msyd --file ./environment.yml
       $CONDA/bin/conda activate msyd
     shell: bash