minor: added mac-os and python 3.9 and 3.10 to github actions

Author: mrava87

.github/workflows/build.yaml

@@ -4,12 +4,12 @@ on: [push, pull_request]
 
 jobs:
   build:
-
-    runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8]
+        platform: [ ubuntu-latest, macos-latest ]
+        python-version: ["3.8", "3.9", "3.10"]
 
+    runs-on: ${{ matrix.platform }}
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}