Fix macOS CI

The `macos-latest` runner has migrated from macOS 12 to macOS 14.
https://github.blog/changelog/2024-04-01-macos-14-sonoma-is-generally-available-and-the-latest-macos-runner-image/
https://github.blog/changelog/2024-05-20-actions-upcoming-changes-to-github-hosted-macos-runners/
I need to keep using macOS 12 for the Xcode 14.0.1 in it.
https://github.com/actions/runner-images/blob/main/images/macos/macos-12-Readme.md#xcode

Alfo fixed the warning `Formula qt5 was renamed to qt@5.`

Author: wh201906

.github/workflows/build-macos.yml

@@ -15,7 +15,7 @@ env:
 
 jobs:
   build:
-    runs-on:  macos-latest
+    runs-on:  macos-12
 
     steps:
       - name: Checkout repo
@@ -34,7 +34,7 @@ jobs:
           brew update
           brew upgrade || echo '::warning::"brew upgrade" failed. Please check the log to see if the artifact is valid.'
           brew install qt@5 || echo '::warning::"brew install qt@5" failed. Please check the log to see if the artifact is valid.'
-          brew link qt5 --force
+          brew link qt@5 --force
 
       - name: Create build directory
         run:  mkdir ${{ runner.temp }}/shadow_build_dir