Use legacy DefaultEventLoopGroup constructor; label Geyser <-> Spigot connection thread

bootstrap/spigot/src/main/java/org/geysermc/platform/spigot/GeyserSpigotInjector.java

@@ -30,6 +30,7 @@ import com.viaversion.viaversion.bukkit.handlers.BukkitChannelInitializer;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.*;
 import io.netty.channel.local.LocalAddress;
+import io.netty.util.concurrent.DefaultThreadFactory;
 import org.bukkit.Bukkit;
 import org.geysermc.connector.bootstrap.GeyserBootstrap;
 import org.geysermc.connector.common.GeyserInjector;
@@ -117,7 +118,7 @@ public class GeyserSpigotInjector extends GeyserInjector {
                         initChannel.invoke(childHandler, ch);
                     }
                 })
-                .group(new DefaultEventLoopGroup())
+                .group(new DefaultEventLoopGroup(0, new DefaultThreadFactory("Geyser Spigot connection thread")))
                 .localAddress(LocalAddress.ANY))
                 .bind()
                 .syncUninterruptibly();

connector/src/main/java/org/geysermc/connector/network/ConnectorServerEventHandler.java

@@ -58,7 +58,8 @@ public class ConnectorServerEventHandler implements BedrockServerEventHandler {
     private static final int MAGIC_RAKNET_LENGTH = 338;
 
     private final GeyserConnector connector;
-    private final DefaultEventLoopGroup eventLoopGroup = new DefaultEventLoopGroup(new DefaultThreadFactory("Geyser player thread"));
+    // There is a constructor that doesn't require inputting threads, but older Netty versions don't have it
+    private final DefaultEventLoopGroup eventLoopGroup = new DefaultEventLoopGroup(0, new DefaultThreadFactory("Geyser player thread"));
 
     public ConnectorServerEventHandler(GeyserConnector connector) {
         this.connector = connector;