Add windows-2019 os

Author: congard

.github/workflows/cmake-multi-platform.yml

@@ -23,13 +23,16 @@ jobs:
       #
       # To add more build types (Release, Debug, RelWithDebInfo, etc.) customize the build_type list.
       matrix:
-        os: [ubuntu-24.04, windows-latest]
+        os: [ubuntu-24.04, windows-latest, windows-2019]
         build_type: [Release]
         c_compiler: [gcc, clang, cl]
         include:
           - os: windows-latest
             c_compiler: cl
             cpp_compiler: cl
+          - os: windows-2019
+            c_compiler: cl
+            cpp_compiler: cl
           - os: ubuntu-24.04
             c_compiler: gcc
             cpp_compiler: g++
@@ -41,6 +44,10 @@ jobs:
             c_compiler: gcc
           - os: windows-latest
             c_compiler: clang
+          - os: windows-2019
+            c_compiler: gcc
+          - os: windows-2019
+            c_compiler: clang
           - os: ubuntu-24.04
             c_compiler: cl