use new action

Author: brentru

.github/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
     - uses: actions/checkout@v2
 
     - name: Set up Python 3.6
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v4
       with:
         python-version: 3.6