Fix export_chat_invite_link not working for bots on channels/supergroups

Telegram still hasn't enabled this for bots...
Closes

compiler/api/source/main_api.tl

@@ -1364,4 +1364,7 @@ langpack.getLanguage#6a596502 lang_pack:string lang_code:string = LangPackLangua
 folders.editPeerFolders#6847d0ab folder_peers:Vector<InputFolderPeer> = Updates;
 folders.deleteFolder#1c295881 folder_id:int = Updates;
 
+// Ports
+channels.exportInvite#c7560885 channel:InputChannel = ExportedChatInvite;
+
 // LAYER 102

pyrogram/client/methods/chats/export_chat_invite_link.py

@@ -52,11 +52,17 @@ class ExportChatInviteLink(BaseClient):
         """
         peer = self.resolve_peer(chat_id)
 
-        if isinstance(peer, (types.InputPeerChannel, types.InputPeerChat)):
+        if isinstance(peer, types.InputPeerChat):
             return self.send(
                 functions.messages.ExportChatInvite(
                     peer=peer
                 )
             ).link
+        elif isinstance(peer, types.InputPeerChannel):
+            return self.send(
+                functions.channels.ExportInvite(
+                    channel=peer
+                )
+            ).link
         else:
             raise ValueError('The chat_id "{}" belongs to a user'.format(chat_id))