docs: Update installation docs to use cargo add

Author: CosmicHorrorDev

keyvalues-parser/README.md

@@ -19,9 +19,8 @@ text.
 
 Just add the library to your `Cargo.toml`
 
-```toml
-[dependencies]
-keyvalues-parser = "0.1.0"
+```console
+$ cargo add keyvalues-parser
 ```
 
 ## Quickstart

keyvalues-serde/README.md

@@ -12,16 +12,19 @@ makes it easy to deal with VDF text files using strongly typed Rust structures.
 
 ## Installation
 
-Just add the following to your `Cargo.toml`
+Just add the library to your `Cargo.toml`
 
-```toml
-[dependencies]
-keyvalues-serde = "0.1.0"
-serde = { version = "1.0.0", features = ["derive"] }
+```console
+$ cargo add keyvalues-serde
 ```
 
 ## Quickstart
 
+```console
+$ cargo add keyvalues-serde
+$ cargo add serde --features derive
+```
+
 ```rust
 use serde::Deserialize;