Component value_type attribute doesn't support Vec, Option, Any, etc

[kellpossible]

With #187 these attributes can be parsed (without this PR these are compile errors), but the following cases don't appear to be supported correctly:

#[derive(utoipa::Component)]
struct Post {
    #[component(value_type = Vec<String>)]
    value: i64,
}

#[derive(utoipa::Component)]
struct Post {
    #[component(value_type = Option<String>)]
    value: i64,
}

#[derive(utoipa::Component)]
struct Post {
    #[component(value_type = Vec<Any>)]
    value: i64,
}

#[derive(utoipa::Component)]
struct Post {
    #[component(value_type = Option<Foo>)]
    value: i64,
}

#[derive(utoipa::Component)]
struct Post {
    #[component(value_type = Vec<Foo>)]
    value: i64,
}

[juhaku]

Haven't thought someone would use value_type for Vec or Option. 😂 So these cases are not implemented. I guess this needs another round of enhancing to support generic types. I'll try to add a support for them.

[juhaku]

The #203 will implement support for above types for IntoParams but another PR is needed for Component support. That will be done shortly.