feat: introduce temporary protocol version 2 (#349)

Author: shumkov

lib/version/protocolVersion.js

@@ -1,11 +1,12 @@
 module.exports = {
-  latestVersion: 1,
+  latestVersion: 2,
   // Even if we bumping protocol version, previous versions of entity structures
   // can be still compatible, that allow to not update clients so often.
   //
   // Minimum compatible versions must be defined for all protocol versions:
   // [protocolVersion]: [minimumCompatibleProtocolVersions]
   compatibility: {
     1: 1,
+    2: 1,
   },
 };