chore: document minimum pnpm and node versions

Author: ItsHarper

CONTRIBUTING.md

@@ -9,7 +9,8 @@ This project is written with [TypeScript](https://www.typescriptlang.org/), a su
 
 ## Developing
 
-codemod expects at least node 16 and pnpm. You can check each of these with `node -v` and `pnpm -v`. Look for instructions on installing node [here](https://nodejs.org) and pnpm [here](https://pnpm.io/).
+codemod expects at least node 18 and pnpm 10. You can check each of these with `node -v` and `pnpm -v`. Look for instructions on installing node [here](https://nodejs.org) and pnpm [here](https://pnpm.io/).
+As long as you have pnpm 10 or later installed globally, pnpm will automatically run the version of pnpm specified in the `packageManager` field in `package.json`.
 
 ### Setup