Update python-package.yml

.github/workflows/python-package.yml

@@ -50,6 +50,7 @@ jobs:
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+      shell: micromamba-shell {0}
     - name: Test with pytest
       shell: micromamba-shell {0}
       run: |