Update python3.6 CI (#96)

* neighbor spelling (assuming we're sticking to American spelling!)

* change to checkoutv4

* change to checkout@v3

* change to pythonv4

* change to ubuntu-20.04

* return to latest ubuntu for 3.7 and 3.8, and separately include 3.6 case

* include pythons up to 3.11

* enclose versions in quotes

* revert spelling changes

.github/workflows/CI.yml

@@ -16,12 +16,15 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: [3.6, 3.7, 3.8]
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        include:
+          - os: ubuntu-20.04
+            python-version: '3.6'
 
     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 }}