ci: remove Python 3.6 and add 3.11 pre-releases (#3005)

* Python 3.6 went EOL Dec 2021
* Python 3.11 is in beta and due for GA release in October 2022

Signed-off-by: Milas Bowman <milas.bowman@docker.com>

Author: milas

.github/workflows/ci.yml

@@ -8,12 +8,12 @@ jobs:
         strategy:
             max-parallel: 1
             matrix:
-                python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+                python-version: ["3.7", "3.8", "3.9", "3.10", "3.11.0-alpha - 3.11.0"]
 
         steps:
-            - uses: actions/checkout@v2
+            - uses: actions/checkout@v3
             - name: Set up Python ${{ matrix.python-version }}
-              uses: actions/setup-python@v2
+              uses: actions/setup-python@v4
               with:
                   python-version: ${{ matrix.python-version }}
             - name: Install dependencies