CI: Remove windows-2019 (which had VS 2019)

GitHub has removed the runner image.

A breakage with CLMUL CRC code occurred with VS 2019 but not 2022,
see b5a5d9e. MS supports VS 2019 for a few more years, so it's
unfortunate that it can no longer be tested on GitHub.

Author: Larhzu

.github/workflows/msvc.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ windows-2019, windows-latest ]
+        os: [ windows-latest ]
 
     runs-on: ${{ matrix.os }}
     timeout-minutes: 10