Update tests

Author: hwdsl2

.github/workflows/test_set_3.yml

@@ -10,7 +10,7 @@ jobs:
     if: github.repository_owner == 'hwdsl2'
     strategy:
       matrix:
-        os: [ubuntu-24.04, ubuntu-22.04, ubuntu-20.04]
+        os: [ubuntu-24.04, ubuntu-22.04]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps: