Add 5G rat type

This add a new rat type for 5G.

Bug: 111453000
Test: build
Change-Id: I57366a1a9f61278cf752c25d54a1af1830bf4575
diff --git a/stats/enums/telephony/enums.proto b/stats/enums/telephony/enums.proto
index fba2e51..4777169 100644
--- a/stats/enums/telephony/enums.proto
+++ b/stats/enums/telephony/enums.proto
@@ -51,6 +51,7 @@
     NETWORK_TYPE_TD_SCDMA = 17;
     NETWORK_TYPE_IWLAN = 18;
     NETWORK_TYPE_LTE_CA = 19;
+    NETWORK_TYPE_NR = 20;
 }
 
 // Signal strength levels, primarily used by android/telephony/SignalStrength.java.