function defaultGetHTML(url, type, email) {
    let msg = 'sign in';
    if (type === 'signup') {
        msg = 'confirm your email address';
    }
    return `<a href="${url}">Click here to ${msg}</a> This msg was sent to ${email}`;
}
defaultGetHTML

@param {URL} url - The url which will trigger sign in flow
@param {string} type - The type of email to send e.g. signin, signup
@param {string} email - The recipient of the email to send
@returns {string} HTML - The HTML content of an email to send