[BUG] Discord Webhook does not match expected format"

[jheaton141]

Describe the bug
Discord webhook does not match the expected format

To Reproduce
Steps to reproduce the behavior:

1. Go to config.yaml
   notifications:
   discord:
   url: "https://discordapp.com/api/webhooks/{YourDiscord}" # [or url: "https://discord.com/api/webhooks/{YourDiscord}"]
   notificationtypes:
   • reacquire
   • unknowndetected
   • startrun
   • endrun
2. run Checkrr

Expected behavior
Expect to send a Discord notification upon trigger

• OS: Docker container
• checkrr Version: 3.6.1

Additional context
time="level=warning msg="Webhook does not match expected format" Discord Connected=false Startup=true".

Proposed change:
regex.FindStringSubmatch(d.URL)
if matches != nil {
if len(matches) == 3 {

--> len(matches) == 3 to len(matches) == 4