moves stuff around so its not a disaster in the root

configs/zsh/ohmyzsh/plugins/cargo/README.md

@@ -0,0 +1,11 @@
+# cargo
+
+This plugin adds completion for the Rust build tool [`Cargo`](https://github.com/rust-lang/cargo).
+
+To use it, add `cargo` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... cargo)
+```
+
+Updated on March 3rd, 2019, from [Cargo 0.34.0](https://github.com/rust-lang/cargo/releases/tag/0.34.0).