CI: Fix windows arm build

Assisted-by: Kimi-k2.6

Author: jdavid

build.ps1

@@ -1,3 +1,5 @@
+$ErrorActionPreference = 'Stop'
+
 if (!(Test-Path -Path "build")) {
     # in case the pygit2 package build/ workspace has not been created by cibuildwheel yet
     mkdir build

docs/install.rst

@@ -309,7 +309,7 @@ variable.  The following recipe shows you how to do it:
 
    git clone --depth=1 -b v1.9.4 https://github.com/libgit2/libgit2.git
    $env:CMAKE_INSTALL_PREFIX = "C:/Dev/libgit2"
-   $env:CMAKE_GENERATOR = "Visual Studio 18 2026"
+   $env:CMAKE_GENERATOR = "Visual Studio 17 2022" # or "Visual Studio 18 2026"
    $env:CMAKE_GENERATOR_PLATFORM = "x64" # or "Win32" or "ARM64"
    cmake -B libgit2/build -S libgit2
    cmake --build libgit2/build --config release --target install

pyproject.toml

@@ -55,7 +55,7 @@ environment.LIBGIT2 = "C:/libgit2_install_x86"
 [[tool.cibuildwheel.overrides]]
 select="*-win_arm64"
 inherit.environment="append"
-environment.CMAKE_GENERATOR = "Visual Studio 18 2026"
+environment.CMAKE_GENERATOR = "Visual Studio 17 2022"
 environment.CMAKE_GENERATOR_PLATFORM = "ARM64"
 environment.CMAKE_INSTALL_PREFIX = "C:/libgit2_install_arm64"
 environment.LIBGIT2 = "C:/libgit2_install_arm64"