Fix compat of the FixturesKernel with Symfony 7

To keep support for Symfony 4.4 which is still supported by
browserkit-driver, the value of the constant is hardcoded in the default
value of the argument instead of referencing the constant, which was
replaced by a new constant name in 5.x with the old name removed in 7.0

Author: stof

src/FixturesKernel.php

@@ -11,7 +11,7 @@
 
 class FixturesKernel implements HttpKernelInterface
 {
-    public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true): Response
+    public function handle(Request $request, $type = 1 /* self::MAIN_REQUEST */ , $catch = true): Response
     {
         $this->prepareSession($request);