Adds update warnings (URL needs to be updated once Spigot resource is created)

src/main/java/net/knarcraft/permissionsigns/PermissionSigns.java

@@ -13,6 +13,7 @@ import net.knarcraft.permissionsigns.manager.PermissionManager;
 import net.knarcraft.permissionsigns.manager.SignManager;
 import net.knarcraft.permissionsigns.thread.PermissionTimeoutThread;
 import net.knarcraft.permissionsigns.thread.SignCreationRequestTimeoutThread;
+import net.knarcraft.permissionsigns.utility.UpdateChecker;
 import net.milkbowl.vault.economy.Economy;
 import net.milkbowl.vault.permission.Permission;
 import org.bukkit.Bukkit;
@@ -145,8 +146,6 @@ public final class PermissionSigns extends JavaPlugin {
         PluginDescriptionFile pluginDescriptionFile = this.getDescription();
         pluginVersion = pluginDescriptionFile.getVersion();
 
-        //TODO: Display a notice in the console if a new version is available (requires Spigot resource first)
-
         //Load config and write the default config if necessary
         FileConfiguration config = this.getConfig();
         config.options().copyDefaults(true);
@@ -159,6 +158,8 @@ public final class PermissionSigns extends JavaPlugin {
 
         SignManager.loadSigns();
         PermissionManager.loadTemporaryPermissions();
+
+        UpdateChecker.checkForUpdate(this, "", () -> pluginVersion, null);
     }
 
     /**