add P3.9 build to the matrix

Author: slayoo

.github/workflows/tests+artifacts+pypi.yml

@@ -17,12 +17,14 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.7", "3.8", "3.10"]
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
         exclude:
           - platform: ubuntu-latest
             python-version: "3.7"
           - platform: windows-latest
             python-version: "3.8"
+          - platform: windows-latest
+            python-version: "3.9"
           - platform: windows-latest
             python-version: "3.10"
     runs-on: ${{ matrix.platform }}