ci: pin Windows SDK version to 10.0.22621.0 for Windows on 32-bit ARM

.github/workflows/msvc.yml

@@ -17,7 +17,7 @@ jobs:
         - { name: Windows static VCRT (x86), flags: -A Win32 -DSDL_FORCE_STATIC_VCRT=ON }
         - { name: Windows (clang-cl x64), flags: -T ClangCL -A x64 }
         - { name: Windows (clang-cl x86), flags: -T ClangCL -A Win32 }
-        - { name: Windows (ARM),          flags: -A ARM }
+        - { name: Windows (ARM),          flags: '-A ARM -DCMAKE_SYSTEM_VERSION="10.0.22621.0"' }  # 10.0.26100.0 dropped ARM32 um and ucrt libraries
         - { name: Windows (ARM64),        flags: -A ARM64 }
         - { name: UWP (x64),              flags: -A x64 -DCMAKE_SYSTEM_NAME=WindowsStore -DCMAKE_SYSTEM_VERSION="10.0" -DSDL_TESTS=OFF, nowerror: true,
             project: VisualC-WinRT/SDL-UWP.sln, projectflags: '/p:Platform=x64 /p:WindowsTargetPlatformVersion=10.0.17763.0' }