Update continuous_integration.yml

.github/workflows/continuous_integration.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
        os: [ubuntu-latest, macos-latest]
-       python-version: ["3.6", "3.7", "3.8", "3.9"]   
+       python-version: ["3.6", "3.7", "3.8"]   
     defaults:
       run:
         shell: bash -l {0}