change python versions in tests

Author: HGWright

.github/workflows/ci-tests.yml

@@ -45,9 +45,9 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["39", "310", "311"]
+        python-version: ["310", "311", "312"]
         include:
-          - python-version: "311"
+          - python-version: "312"
             cov-report: "--cov-report=xml --cov"
             codecov: "codecov"