Merge pull request #510 from pinkeen/fix-build-websockets-bump

Fix broken build with latest Arduino libs - bump Websockets to ~2.2.0

platformio.ini

@@ -20,7 +20,7 @@ lib_deps_external =
   ArduinoJson@~6.10.1
   PubSubClient@~2.7
   ratkins/RGBConverter@07010f2
-  WebSockets@~2.1.2
+  WebSockets@~2.2.0
   CircularBuffer@~1.2.0
   PathVariableHandlers@~2.0.0
   RichHttpServer@~2.0.2