chore: fix types in FileDescriptorProto

Author: kafkiansky

src/Compiler/FileDescriptorProto.php

@@ -24,9 +24,9 @@
      */
     public function __construct(
         #[Reflection\Field(1, Reflection\StringT::T)]
-        public ?string $name = null,
+        public string $name,
         #[Reflection\Field(2, Reflection\StringT::T)]
-        public ?string $package = null,
+        public string $package,
         #[Reflection\Field(3, new Reflection\ListT(Reflection\StringT::T))]
         public array $dependencies = [],
         #[Reflection\Field(10, new Reflection\ListT(Reflection\Int32T::T))]