Add conflict message when building protobuf and grpc (#653)

Author: crazywhalecc

src/SPC/builder/extension/protobuf.php

@@ -15,5 +15,9 @@ public function validate(): void
         if ($this->builder->getPHPVersionID() < 80000 && getenv('SPC_SKIP_PHP_VERSION_CHECK') !== 'yes') {
             throw new \RuntimeException('The latest protobuf extension requires PHP 8.0 or later');
         }
+        // protobuf conflicts with grpc
+        if ($this->builder->getExt('grpc') !== null) {
+            throw new \RuntimeException('protobuf conflicts with grpc, please remove grpc or protobuf extension');
+        }
     }
 }