v0.25.0

@samva/cli@0.25.0

Set custom headers with samva email send --header

samva email send --header 'Name: Value' (repeatable) sets email.headers. The name is the text
before the first colon and the value is the rest. A pair with no colon, no name, or no value is
rejected before the request. The API rejects reserved names and headers past its limits.