v2.7.0

Added:

• [dnsprovider] Add DNS provider for namesilo
• [dnsprovider] Add DNS provider for versio.nl

Changed:

• [dnsprovider] Update DNS providers libs.
• [dnsprovider] joker: support username and password.
• [dnsprovider] Vultr: Switch to official client

Fixed:

• [dnsprovider] otc: Prevent sending empty body.