downgrade actions setup

.github/workflows/tests.yml

@@ -43,7 +43,7 @@ jobs:
     steps:
     # Python and pip setup
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -55,15 +55,15 @@ jobs:
       run: |
         echo "::set-output name=dir::$(pip cache dir)"
     - name: pip cache
-      uses: actions/cache@v4
+      uses: actions/cache@v2
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
         restore-keys: |
           ${{ runner.os }}-pip-
 
     # package setup
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v3
 
     - name: Install dependencies
       if: matrix.python-version != '3.6' && matrix.python-version != '3.7'