change webhook name

Creating webhooks fail on:

```
ERRO[9779449] could not transmit message to discord         error="could not create webhook: HTTP 400 Bad Request, {\"code\": 50035, \"errors\": {\"name\": {\"_errors\": [{\"code\": \"USERNAME_INVALID_CONTAINS\", \"message\": \"Username cannot contain \\\"discord\\\"\"}]}}, \"message\": \"Invalid Form Body\"}" msg.avatar="https://cdn.discordapp.com/avatars/83386293446246400/7170be0d5936eb4beec03454d6385721.png" msg.channel=1028406920282910821 msg.content=test msg.username=qaisjp
```

bridge/discord.go

@@ -61,7 +61,7 @@ func newDiscord(bridge *Bridge, botToken, guildID string) (*discordBot, error) {
 }
 
 func (d *discordBot) Open() error {
-	d.transmitter = transmitter.New(d.Session, d.guildID, "go-discord-irc", true)
+	d.transmitter = transmitter.New(d.Session, d.guildID, "irc-bridge", true)
 	d.transmitter.Log = logrus.NewEntry(logrus.StandardLogger())
 	if err := d.transmitter.RefreshGuildWebhooks(nil); err != nil {
 		return fmt.Errorf("failed to refresh guild webhooks: %w", err)