Disable fail-fast

PHP 8.4 currently fails because the version is installed version
is too old. Avoid cancelling other CI jobs because of that.

Author: nikic

.github/workflows/main.yml

@@ -39,6 +39,7 @@ jobs:
           - "8.2"
           - "8.3"
           - "8.4"
+      fail-fast: false
     steps:
       - name: "Checkout"
         uses: "actions/checkout@v4"