Add notice about PacketEvents requirement update banner and resize gif

Took 10 minutes

Author: CitralFlo

README.md

@@ -13,6 +13,9 @@
 
 ### Information
 
+## EternalCombat requires PacketEvents plugin to work.
+You can download it from [here](https://modrinth.com/plugin/packetevents)
+
 EternalCombat 2.0 has been tested on Minecraft versions **1.17.1 to 1.21.5**, but it should work seamlessly on most
 other versions too.
 If you run into any compatibility issues, please let us know in