removing python 3.6 and 3.7

Author: karen-avetisyan-mc

.github/workflows/test.yml

@@ -15,16 +15,10 @@ jobs:
     strategy:
       matrix:
         python-version:
-          - 3.6
-          - 3.7
           - 3.8
           - 3.9
         include:
           - os: "ubuntu-latest"
-          # There is no build for Python 3.6 in ubuntu>20.04.
-          # This unclude can be removed when we drop support for Python 3.6.
-          - os: "ubuntu-20.04"
-            python-version: "3.6"
     steps:
       - uses: actions/checkout@v2
         with: