[ci] use python3.0 matrix to test 2.7

Author: fangq

.github/workflows/run_test.yml

@@ -7,16 +7,16 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["2.7", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.0", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
-      - if: matrix.python-version == '2.7'
-        run: sudo ln -sf /usr/bin/python2.7 /usr/bin/python
       - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+      - if: matrix.python-version == '3.0'
+        run: sudo ln -sf /usr/bin/python2.7 /usr/bin/python
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip