This is a X-GitHub Header port
* repository for repository webhooks (matches GitHub)
* organization for organization webhooks (matches GitHub)
* user for user webhooks (Gitea specific)
* system for system webhooks (Gitea specific)
* default for default hooks needs testing (Gitea specific)
- `X-Gitea-Hook-Installation-Target-Type`
- `X-GitHub-Hook-Installation-Target-Type`