aarch64: add support for Windows on ARM

Add support for building Microsoft Git on Windows/ARM64.
We use a custom 1ES pool that we maintain to provide ARM64 GitHub
runners that have the latest Git for Windows ARM64 installed.

Signed-off-by: Matthew John Cheetham <[email protected]>
Signed-off-by: Johannes Schindelin <[email protected]>

Author: mjcheetham

.github/workflows/clangarm64-build.yml

@@ -9,7 +9,7 @@ defaults:
 
 jobs:
   clang-build:
-    runs-on: [Windows, ARM64]
+    runs-on: ['self-hosted', '1ES.Pool=github-arm64-pool']
     env:
       NO_PERL: 1
     steps: