fix autocloseable executors

src/main/java/wtf/beatrice/hidekobot/HidekoBot.java

@@ -187,8 +187,10 @@ public class HidekoBot
 
         // update slash commands (delayed)
         final boolean finalForceUpdateCommands = forceUpdateCommands;
-        Executors.newSingleThreadScheduledExecutor().schedule(() -> // todo: try-with-resources
-                CommandUtil.updateSlashCommands(finalForceUpdateCommands), 1, TimeUnit.SECONDS);
+        try (ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor()) {
+            executor.schedule(() -> CommandUtil.updateSlashCommands(finalForceUpdateCommands),
+                    1, TimeUnit.SECONDS);
+        }
 
         // set the bot's status
         jda.getPresence().setStatus(OnlineStatus.ONLINE);

src/main/java/wtf/beatrice/hidekobot/commands/slash/DieCommand.java

@@ -10,6 +10,7 @@ import wtf.beatrice.hidekobot.HidekoBot;
 import wtf.beatrice.hidekobot.objects.commands.SlashCommandImpl;
 
 import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
 public class DieCommand extends SlashCommandImpl
@@ -28,7 +29,9 @@ public class DieCommand extends SlashCommandImpl
             event.reply("Sorry, only the bot owner can run this command!").setEphemeral(true).queue();
         } else {
             event.reply("Going to sleep! Cya ✨").queue();
-            Executors.newSingleThreadScheduledExecutor().schedule(HidekoBot::shutdown, 3, TimeUnit.SECONDS);
+            try (ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor()) {
+                executor.schedule(HidekoBot::shutdown, 3, TimeUnit.SECONDS);
+            }
         }
     }
 }

src/main/java/wtf/beatrice/hidekobot/util/Logger.java

@@ -3,6 +3,7 @@ package wtf.beatrice.hidekobot.util;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
 @Deprecated(since = "0.5.16", forRemoval = true)
@@ -49,7 +50,9 @@ public class Logger<T>
     {
         // create a new scheduled executor with an anonymous runnable...
         //... after waiting <delay> seconds.
-        Executors.newSingleThreadScheduledExecutor().schedule(() -> log(message), delay, TimeUnit.SECONDS);
+        try (ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor()) {
+            executor.schedule(() -> log(message), delay, TimeUnit.SECONDS);
+        }
 
     }