Fix CI on macos-11

Author: nicolas-grekas

.github/workflows/unit-tests.yml

@@ -148,7 +148,7 @@ jobs:
           echo "::endgroup::"
 
       - name: Patch return types
-        if: "matrix.php == '8.1' && ! matrix.mode && matrix.os == 'ubuntu-20.04'"
+        if: "matrix.php == '8.1' && ! matrix.mode && matrix.os != 'macos-11'"
         run: |
           sed -i 's/"\*\*\/Tests\/"//' composer.json
           composer install -q --optimize-autoloader
@@ -222,7 +222,7 @@ jobs:
           [[ ! $X ]] || (exit 1)
 
       - name: Run tests with SIGCHLD enabled PHP
-        if: "matrix.php == '7.2' && ! matrix.mode"
+        if: "matrix.php == '7.2' && ! matrix.mode && matrix.os != 'macos-11'"
         run: |
           mkdir build
           cd build