Adds a new item to allow arena re-tries

Prevents a NumberFormatException if the record number is invalid
Updates Spigot to 1.20

src/main/java/net/knarcraft/minigames/arena/AbstractArenaSession.java

@@ -15,7 +15,7 @@ public abstract class AbstractArenaSession implements ArenaSession {
     private final @NotNull ArenaGameMode gameMode;
     private final @NotNull Player player;
     protected int deaths;
-    protected final long startTime;
+    protected long startTime;
     protected PlayerEntryState entryState;
 
     /**
@@ -47,6 +47,14 @@ public abstract class AbstractArenaSession implements ArenaSession {
         player.sendMessage(Message.SUCCESS_ARENA_QUIT.getMessage());
     }
 
+    @Override
+    public void reset() {
+        this.deaths = 0;
+        this.startTime = System.currentTimeMillis();
+        PlayerTeleporter.teleportPlayer(this.player, this.arena.getSpawnLocation(), false, false);
+        this.entryState.setArenaState();
+    }
+
     /**
      * Announces a record set by this player
      *

src/main/java/net/knarcraft/minigames/arena/ArenaSession.java

@@ -47,4 +47,9 @@ public interface ArenaSession {
      */
     @NotNull ArenaGUI getGUI();
 
+    /**
+     * Resets the session to allow a player to try again
+     */
+    void reset();
+
 }

src/main/java/net/knarcraft/minigames/arena/parkour/ParkourArenaSession.java

@@ -116,6 +116,12 @@ public class ParkourArenaSession extends AbstractArenaSession {
         return new ParkourGUI(player);
     }
 
+    @Override
+    public void reset() {
+        this.reachedCheckpoint = null;
+        super.reset();
+    }
+
     @Override
     protected void removeSession() {
         // Remove this session for game sessions to stop listeners from fiddling more with the player