Update github test workflow.

This updates the test workflow to fix several issues:

- Python 3.6 is no longer available on the test hosts.
- Node 12 is deprecated, and needs to be replaced with 16.
- The name of the node step had a typo in it (Instal -> Install).

Author: davidt

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy-3.8']
+        python-version: ['3.7', '3.8', '3.9', '3.10', 'pypy-3.8']
         django-version: ['2.2', '3.0', '3.1', '3.2', '4.0', 'main']
         exclude:
           - python-version: '3.6'
@@ -40,9 +40,9 @@ jobs:
     - name: Set up Node
       uses: actions/setup-node@v1
       with:
-        node-version: '12'
+        node-version: '16'
 
-    - name: Instal Node dependencies
+    - name: Install Node dependencies
       run: npm install
 
     - name: Get pip cache dir