Adds arm64 build target in cmake.yml

Author: taku910

.github/workflows/cmake.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest, macos-latest ]
-        arch: [ '' ]
+        arch: [ x64, arm64 ]
         include:
           - os: windows-latest
             arch: Win32