Test on 3.15 and 3.15t on CI

Author: lysnikolaou

.github/workflows/main.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.13t', '3.14', '3.14t']
+        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.13t', '3.14', '3.14t', '3.15', '3.15t']
         with-psutil: [false]
         include:
           - python-version: '3.14t'