fix syntax error in GitHub Action (#220)

* fix syntax error in GitHub Action

* downgrade python to 3.9

3.10 has not been prepared well

Author: njzjz

.github/workflows/test_import.yml

@@ -10,9 +10,9 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v2
-        with:
-            python-version: '3.x'
-            architecture: 'x64'
+      with:
+        python-version: '3.9'
+        architecture: 'x64'
     - run: python -m pip install .
     - run: python -c 'import dpdata'