GitHub Action: Add Python 3.9 and Update MariaDB Connector C 3.1.11 (#453)

Author: supervirus

.github/workflows/windows.yaml

@@ -5,12 +5,13 @@ on:
     branches:
       - master
   create:
+  workflow_dispatch:
 
 jobs:
   build:
     runs-on: windows-latest
     env:
-      CONNECTOR_VERSION: "3.1.9"
+      CONNECTOR_VERSION: "3.1.11"
     steps:
 
       - name: Cache Connector
@@ -63,6 +64,8 @@ jobs:
         shell: cmd
         working-directory: ../mysqlclient
         run: |
+          py -3.9 -m pip install -U setuptools wheel pip
+          py -3.9 setup.py bdist_wheel
           py -3.8 -m pip install -U setuptools wheel pip
           py -3.8 setup.py bdist_wheel
           py -3.7 -m pip install -U setuptools wheel pip
@@ -81,6 +84,8 @@ jobs:
         working-directory: ../mysqlclient/dist
         run: |
           ls -la
+          py -3.9 -m pip install --no-index --find-links . mysqlclient
+          py -3.9 -c "import MySQLdb; print(MySQLdb.version_info)"
           py -3.8 -m pip install --no-index --find-links . mysqlclient
           py -3.8 -c "import MySQLdb; print(MySQLdb.version_info)"
           py -3.7 -m pip install --no-index --find-links . mysqlclient