Update main.yml

Author: hamelsmu

.github/workflows/main.yml

@@ -25,7 +25,7 @@ jobs:
       fail-fast: false
       matrix:
         os:  [ubuntu, windows, macos]
-        py:  [3.7, 3.8, 3.9, 3.10]
+        py:  ["3.7", "3.8", "3.9", "3.10"]
         include:
           - os: windows
             shell: "/usr/bin/bash"