feat(bot): Restart heartbeat on shard reconnect.

payphone/bot.py

@@ -124,8 +124,15 @@ class Payphone(commands.AutoShardedBot):
 
         print(f"Shard {shard_id} was resumed!")
 
-    async def on_shard_disconnect(shard_id: int) -> None:
+    async def on_shard_connect(self, shard_id: int) -> None:
-    self.update_heartbeat.cancel()
+        try:
+            self.update_heartbeat.start()
+
+        except RuntimeError:
+            pass
+
+    async def on_shard_disconnect(self, shard_id: int) -> None:
+        self.update_heartbeat.cancel()
 
     async def get_or_fetch_channel(
         self, channel_id: int