use macos-11

Author: mike-hunhoff

.github/workflows/tests.yml

@@ -33,7 +33,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-20.04, windows-2019, macos-10.15]
+        os: [ubuntu-20.04, windows-2019, macos-11]
         # across all operating systems
         python-version: ["3.7", "3.10"]
         include: