Update pypy.yml

Author: gliptak

.github/workflows/pypy.yml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Setup Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python-version }}
           architecture: x64