Add kMaxValue alias to KeyUpdateReason enum.

PiperOrigin-RevId: 338132321
Change-Id: Ie13f3437ee6eb8caebb1cac9cf3eea09264ffc59

quic/core/quic_types.h

diff --git a/quic/core/quic_types.h b/quic/core/quic_types.h
index 514c91f..5152a15 100644
--- a/quic/core/quic_types.h
+++ b/quic/core/quic_types.h
@@ -806,6 +806,7 @@
   kLocalForInteropRunner = 3,
   kLocalAeadConfidentialityLimit = 4,
   kLocalKeyUpdateLimitOverride = 5,
+  kMaxValue = kLocalKeyUpdateLimitOverride,
 };
 
 QUIC_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os,