Update CI to use ubuntu-latest and add Python 3.12, 3.13

Switched from ubuntu-20.04 to ubuntu-latest for consistency and future-proofing. Added support for Python 3.12 and 3.13 to ensure compatibility with the latest Python versions.

Author: andrii-porokhnavets

.github/workflows/main.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os:
-          - "ubuntu-20.04"
+          - "ubuntu-latest"
           - "windows-latest"
           - "macos-latest"
         python:
@@ -19,6 +19,8 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
+          - "3.12"
+          - "3.13"
         # Workaround from https://github.com/actions/runner-images/issues/9770
         exclude:  # Python < v3.8 does not support Apple Silicon ARM64.
           - python: "3.6"