Fix extra respawn packet byte on <1.21.2 (#1448)

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/RespawnPacket.java

@@ -278,7 +278,7 @@ public class RespawnPacket implements MinecraftPacket {
       ProtocolUtils.writeVarInt(buf, portalCooldown);
     }
 
-    if (version.noLessThan(ProtocolVersion.MINECRAFT_1_12_1)) {
+    if (version.noLessThan(ProtocolVersion.MINECRAFT_1_21_2)) {
       ProtocolUtils.writeVarInt(buf, seaLevel);
     }