CI: pin Windows runner to 2022

Pin build-windows to windows-2022 to avoid v143 toolset availability drift on windows-latest, especially for ARM64.

Document this CI change in CHANGELOG.md under Unreleased.

Author: kristjanvalur

.github/workflows/buildcommit.yml

@@ -128,7 +128,7 @@ jobs:
         path: lib/${{ matrix.abi }}/libstackman.a
 
   build-windows:
-    runs-on: windows-latest
+    runs-on: windows-2022
     strategy:
       matrix:
         platform: [x86, x64, arm64]

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+- CI: pinned Windows runner to `windows-2022` (from `windows-latest`) to keep VS2022 v143 toolset availability stable for ARM64 builds
+
 ### Fixed
 - Fixed amd64 (sysv_x86_64 GCC) restore callback stack-pointer argument to pass the active switched stack pointer
 - Added assertion coverage in `tests/test.c` to detect incorrect restore callback stack pointer on amd64