Fix failing test suite by updating macOS

Author: clue

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
 
   PHPUnit-macOS:
     name: PHPUnit (macOS)
-    runs-on: macos-10.15
+    runs-on: macos-12
     continue-on-error: true
     steps:
       - uses: actions/checkout@v2