connector: handle supergroup upgrades (#118)

Co-authored-by: Tulir Asokan <tulir@maunium.net>

pkg/connector/config.go

@@ -82,6 +82,8 @@ type TelegramConfig struct {
 	AlwaysCustomEmojiReaction bool `yaml:"always_custom_emoji_reaction"`
 
 	SavedMessagesAvatar id.ContentURIString `yaml:"saved_message_avatar"`
+
+	AlwaysTombstoneOnSupergroupMigration bool `yaml:"always_tombstone_on_supergroup_migration"`
 }
 
 func (c TelegramConfig) ShouldBridge(participantCount int) bool {
@@ -120,6 +122,7 @@ func upgradeConfig(helper up.Helper) {
 	helper.Copy(up.Bool, "sync", "direct_chats")
 	helper.Copy(up.Bool, "always_custom_emoji_reaction")
 	helper.Copy(up.Str, "saved_message_avatar")
+	helper.Copy(up.Bool, "always_tombstone_on_supergroup_migration")
 }
 
 func (tg *TelegramConnector) GetConfig() (example string, data any, upgrader up.Upgrader) {