Add missing include <string>

This files was using std::string without including <string>
so this CL adds the missing include.

Bug: b/261755036
Change-Id: Id5a2ed26055a430455dcd2fb1e78bd46ccf9e69b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/70188
Reviewed-by: Geoff Lang <geofflang@google.com>
Commit-Queue: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
diff --git a/src/Vulkan/Debug/EventListener.hpp b/src/Vulkan/Debug/EventListener.hpp
index 3ab287c..c879564 100644
--- a/src/Vulkan/Debug/EventListener.hpp
+++ b/src/Vulkan/Debug/EventListener.hpp
@@ -17,6 +17,8 @@
 
 #include "ID.hpp"
 
+#include <string>
+
 namespace vk {
 namespace dbg {