Update ci.yml

Author: qhangz

.github/workflows/ci.yml

@@ -15,7 +15,6 @@ jobs:
       fail-fast: false
       matrix:
         platform:
-        - { name: Windows VS2019, os: windows-2019  }
         - { name: Windows VS2022, os: windows-2022  }
         - { name: Linux GCC,      os: ubuntu-latest }
         - { name: Linux Clang,    os: ubuntu-latest, flags: -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ }