ci(unittests): be explicit about ubuntu version; run on both 22.04,24.04

Author: 3np

.github/workflows/unittests.yml

@@ -8,7 +8,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-13, ubuntu-latest]
+        os:
+          - macos-13
+          - ubuntu-22.04
+          - ubuntu-24.04
         python-version:
           - "3.8"
           - "3.12"