Test on macos for completeness

Author: Zachary Eisinger

.github/workflows/workflow.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ${{ matrix.operating-system }}
     strategy:
       matrix:
-        operating-system: [ubuntu-latest, windows-latest]
+        operating-system: [ubuntu-latest, windows-latest, macOS-latest]
     steps:
     - name: Checkout
       uses: actions/checkout@master