ci: Add Python 3.15 to CI workflow matrix (#1503)

Author: dbanty

.github/workflows/checks.yml

@@ -11,7 +11,7 @@ jobs:
   test:
     strategy:
       matrix:
-        python: [ "3.11", "3.12", "3.13", "3.14" ]
+        python: [ "3.11", "3.12", "3.13", "3.14", "3.15" ]
         os: [ ubuntu-latest, macos-latest, windows-latest ]
     runs-on: ${{ matrix.os }}
     steps: