pw_router: Add missing includes

Change-Id: Ibb330467c058da637fff3323d9375beecdae10fc
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/98904
Pigweed-Auto-Submit: Dennis Kormalev <denk@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Alexei Frolov <frolv@google.com>
diff --git a/pw_router/public/pw_router/packet_parser.h b/pw_router/public/pw_router/packet_parser.h
index c4ecc8a..7b9b2d0 100644
--- a/pw_router/public/pw_router/packet_parser.h
+++ b/pw_router/public/pw_router/packet_parser.h
@@ -13,6 +13,7 @@
 // the License.
 #pragma once
 
+#include <cstdint>
 #include <optional>
 #include <span>