Move 3.7.9 pylint check to ubuntu-20.04

.github/workflows/pylint.yml

@@ -5,12 +5,32 @@ name: pylint check on push and PR
 on: [push, pull_request]
 
 jobs:
+  pylint-check-old:
+    runs-on: ubuntu-20.04
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.7.9"]
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pylint
+    - name: Analysing the code with pylint
+      run: |
+        cd python
+        pylint --rcfile=ctsm/.pylintrc --fail-under=0 ctsm
   pylint-check:
      runs-on: ubuntu-latest
      strategy:
        fail-fast: false
        matrix:
-         python-version: ["3.7.9", "3.8", "3.9", "3.10", "3.11", "3.12"]
+         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
      steps:
      - uses: actions/checkout@v4
      - name: Set up Python ${{ matrix.python-version }}