chore: bump engine.io-client to version 2.1.0

Diff: socketio/engine.io-client-java@engine.io-client-2.0.0...engine.io-client-2.1.0
Release notes: https://github.com/socketio/engine.io-client-java/releases/tag/engine.io-client-2.1.0

Author: darrachequesne

pom.xml

@@ -62,7 +62,7 @@
     <dependency>
       <groupId>io.socket</groupId>
       <artifactId>engine.io-client</artifactId>
-      <version>2.0.0</version>
+      <version>2.1.0</version>
     </dependency>
     <dependency>
       <groupId>org.json</groupId>