[Cadence 1.0] Add ProtocolStateVersionUpgrade service event

contracts/NodeVersionBeacon.cdc

@@ -18,6 +18,10 @@
 /// The contract itself can be used to query the current version and the next upcoming version.
 access(all) contract NodeVersionBeacon {
 
+    /// =========================
+    /// Execution State Versioning
+    /// =========================
+
     /// Struct representing software version as Semantic Version
     /// along with helper functions
     /// For reference, see https://semver.org/
@@ -134,10 +138,11 @@ access(all) contract NodeVersionBeacon {
         )
     }
 
-    /// Event emitted when the version table is updated.
-    /// It contains the current version and all the upcoming versions
-    /// sorted by block height.
-    /// The sequence increases by one each time an event is emitted.
+    /// A service event emitted when the version table is updated.
+    /// The version is the software version which must be used for executing a height range of blocks.
+    /// The version pertains to Execution and Verification Nodes.
+    /// The table contains the current version and all the upcoming versions sorted by block height.
+    /// The sequence increases by one each time an event is emitted. 
     /// It can be used to verify no events were missed.
     access(all) event VersionBeacon(
         versionBoundaries: [VersionBoundary],
@@ -280,6 +285,13 @@ access(all) contract NodeVersionBeacon {
 
             emit NodeVersionBoundaryFreezePeriodChanged(freezePeriod: newFreezePeriod)
         }
+
+        /// Emits the given protocol state version upgrade event. If the version and active are
+        /// valid, this will cause the Protocol State to upgrade its model version when the
+        /// event is incorporated.
+        access(all) fun emitProtocolStateVersionUpgrade(newProtocolVersion: UInt64, activeView: UInt64) {
+            emit ProtocolStateVersionUpgrade(newProtocolVersion: newProtocolVersion, activeView: activeView)
+        }
     }
 
     /// Heartbeat resource that emits the version beacon event and keeps track of upcoming versions.
@@ -495,6 +507,17 @@ access(all) contract NodeVersionBeacon {
         return self.versionBoundaryBlockList[0]
     }
 
+    /// =========================
+    /// Protocol State Versioning
+    /// =========================
+
+    /// A service event which is emitted to indicate that the Protocol State version is being upgraded.
+    /// This acts as a signal to begin using the upgraded Protocol State version 
+    /// after this service event is sealed, and after view `activeView` is entered.
+    /// Nodes running a software version which does not support `newProtocolVersion`
+    /// will stop processing new blocks when they reach view `activeAtView`.
+    access(all) event ProtocolStateVersionUpgrade(newProtocolVersion: UInt64, activeView: UInt64)
+
     init(versionUpdateFreezePeriod: UInt64) {
         self.AdminStoragePath = /storage/NodeVersionBeaconAdmin
         self.HeartbeatStoragePath = /storage/NodeVersionBeaconHeartbeat