ARM64: Install clang on build-installers flavor

When adding ARM64 support to this Action, I overlooked something
regarding the `build-installers` flavor:

> In addition to building `mingw-w64-git`, this flavor allows bundling
> Git for Windows' artifacts such as the installer and the Portable Git.

This is now hurting me when setting up a CI pipeline, as `clang`/`llvm`
are missing when using the `build-installers` flavor and trying to
build `mingw-w64-git`.

Signed-off-by: Dennis Ameling <dennis@dennisameling.com>

Author: dennisameling

dist/index.js

@@ -38,7 +38,11 @@ async function installArm64Dependencies(
     'mingw-w64-clang-aarch64-pcre2',
     'mingw-w64-clang-aarch64-libssp'
   ]
-  if (flavor === 'full' || flavor === 'makepkg-git') {
+  if (
+    flavor === 'full' ||
+    flavor === 'makepkg-git' ||
+    flavor === 'build-installers'
+  ) {
     packages.push(
       'mingw-w64-clang-aarch64-toolchain',
       'mingw-w64-clang-aarch64-asciidoc'