Merge pull request #138 from kshtsk/wip-drop-ubuntu2004

ci: use ubuntu 24.04 instead of 20.04

Author: zmc

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: ["ubuntu-20.04"]
+        os: ["ubuntu-24.04"]
         python: [3.9, 3.11, 3.13]
     steps:
       - uses: actions/checkout@v2