revert

Author: Nissan Pow

.github/workflows/metaflow.s3_tests.yml

@@ -21,7 +21,7 @@ jobs:
       labels: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest]
+        os: [macos-latest, ubuntu-20.04]
         ver: ['3.10']
 
     steps: