Thaw/v0.5

[luoxiaozero]

This is meant to prepare for a 0.5.0-alpha release.

It will include the following breaking changes:

• Update leptos to v0.8.0-alpha.
• RatingColor adds Marigold attribute.

---

• Theme is changed to use getset.

Reason: When adding new components requires changing ColorTheme, it is very easy to make breaking changes.

example:

// 0.4
let _ = theme.common.font_weight_bold;
let _ = theme.color.color_brand_background;
theme.common.font_weight_bold = "700".to_string();
theme.color.color_brand_background = "#f5222d".to_string();

// 0.5
let _ = theme.common.font_weight_bold();
let _ = theme.color.color_brand_background();
theme.common.set_font_weight_bold("700".to_string());
theme.color.set_color_brand_background("#f5222d".to_string());