Fix CORS support

[johnf]

cors.default() doesn't allow anything, so the GET method needs to be enabled.

From the docs https://docs.rs/actix-cors/latest/src/actix_cors/builder.rs.html#494-499

impl Default for Cors {
    /// A restrictive (security paranoid) set of defaults.
    ///
    /// *No* allowed origins, methods, request headers or exposed headers. Credentials
    /// not supported. No max age (will use browser's default).
    fn default() -> Cors {

[latin-1]

Thanks