add mcmmo power level requirement

src/main/java/sh/okx/rankup/requirements/requirement/McMMOPowerLevelRequirement.java

@@ -0,0 +1,31 @@
+package sh.okx.rankup.requirements.requirement;
+
+import com.gmail.nossr50.util.player.UserManager;
+import org.bukkit.entity.Player;
+import sh.okx.rankup.Rankup;
+import sh.okx.rankup.requirements.Requirement;
+
+public class McMMOPowerLevelRequirement extends Requirement {
+  public McMMOPowerLevelRequirement(Rankup plugin) {
+    super(plugin, "mcmmo-power-level");
+  }
+
+  protected McMMOPowerLevelRequirement(Requirement clone) {
+    super(clone);
+  }
+
+  @Override
+  public boolean check(Player player) {
+    return getRemaining(player) <= 0;
+  }
+
+  @Override
+  public double getRemaining(Player player) {
+    return Math.max(0, getValueInt() - UserManager.getPlayer(player).getPowerLevel());
+  }
+
+  @Override
+  public Requirement clone() {
+    return new McMMOPowerLevelRequirement(this);
+  }
+}