Fix crates.io repository URLs and READMEs for subsecond and manganis crates (#5013)

* Update repository URL and add README reference

* Fix repository URL and add readme field

Updated repository URL to point to the correct path and added a readme field.

* Update repository URL in Cargo.toml

* Update repository URL in Cargo.toml

* Update repository URL and add readme path

* Fix repository URL in Cargo.toml

---------

Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

packages/manganis/manganis-macro/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 authors = ["Evan Almloff"]
 description = "Ergonomic, automatic, cross crate asset collection and optimization"
 license = "MIT OR Apache-2.0"
-repository = "https://github.com/DioxusLabs/manganis/"
+repository = "https://github.com/DioxusLabs/dioxus/tree/main/packages/manganis/manganis-macro"
 homepage = "https://dioxuslabs.com"
 keywords = ["assets"]