zenform credentials TOML format

.zenform.toml

# ~/.zenform
[[credentials]]
    [credentials.production]
    auth_type = "basic"
    subdomain = "zenform"
    email     = "zenform@example.com"
    password  = "password"
    
    [credentials.sandbox]
    auth_type = "basic"
    subdomain = "zenform012345"
    email     = "zenform+sandbox@example.com"
    password  = "password"
    
[[credentials]]
    [credentials.production]
    auth_type = "token"
    subdomain = "nukosuke"
    email     = "nukosuke@example.com"
    api_token = "0123456abcdefg"
    
    [credentials.sandbox]
    auth_type = "token"
    subdomain = "nukosuke012345"
    email     = "nukosuke+sandbox@example.com"
    api_token = "0123456abcdefg"