chore: remove deprecated image form CI matrix

Author: xmatthias

.github/workflows/ci.yml

@@ -24,7 +24,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ "ubuntu-20.04", "ubuntu-22.04", "ubuntu-24.04" ]
+        os: [ "ubuntu-22.04", "ubuntu-24.04" ]
         python-version: ["3.10", "3.11", "3.12"]
 
     steps: