test on all 3 OS's

Author: svlandeg

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ windows-latest ]
+        os: [ ubuntu-latest, windows-latest, macos-latest ]
         python-version:
           - "3.8"
           - "3.9"