CI: Abandon testing with Python 3.6

Python 3.6 requires too many deprecated dependencies. Running test
under Python 3.6 is getting too complicated.

Signed-off-by: Martin Belanger <martin.belanger@dell.com>

.github/workflows/pylint.yml

@@ -26,7 +26,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
 
     steps:
       - name: "CHECKOUT: nvme-stas"