Update CONTRIBUTING guide to use pnpm

Author: fvictorio

CONTRIBUTING.md

@@ -12,37 +12,37 @@ We use a [GitHub project](https://github.com/orgs/NomicFoundation/projects/4/vie
 
 ## Project structure
 
-This repository is a monorepo handled with [Yarn v1](https://classic.yarnpkg.com/lang/en/) and [Yarn workspaces](https://classic.yarnpkg.com/en/docs/workspaces/).
+This repository is a monorepo handled with [pnpm](https://pnpm.io/) and [pnpm workspaces](https://pnpm.io/workspaces).
 
 There's a folder for each subproject in `packages/`. All of them are plugins, except for `/packages/hardhat-core` which is the main project (i.e. the one that's published as [hardhat](https://npmjs.com/package/hardhat) in npm).
 
 ## Installing
 
-To install the project's dependencies, run `yarn` in the root directory of the repository.
+To install the project's dependencies, run `pnpm i` in the root directory of the repository.
 
 ## Building the projects
 
-Plugins require hardhat to be built or tested. Our recommendation is to run `yarn watch` from the root folder. This will keep everything compiled, and these problems will be avoided.
+Plugins require hardhat to be built or tested. Our recommendation is to run `pnpm watch` from the root folder. This will keep everything compiled, and these problems will be avoided.
 
 ## Testing
 
 All tests are written using [mocha](https://mochajs.org) and [chai](https://www.chaijs.com).
 
 ### Per-package
 
-You can run a package's tests by executing `yarn test` inside its folder.
+You can run a package's tests by executing `pnpm test` inside its folder.
 
 ### Entire project
 
-You can run all the tests at once by running `yarn test` from the root folder.
+You can run all the tests at once by running `pnpm test` from the root folder.
 
 ## Code formatting
 
 We use [Prettier](https://prettier.io/) to format all the code without any special configuration. Whatever Prettier does is considered The Right Thing. It's completely fine to commit non-prettied code and then reformat it in a later commit.
 
 We also have [eslint](https://eslint.org/) installed in all the projects. It checks that you have run Prettier and forbids some dangerous patterns.
 
-The linter is always run in the CI, so make sure it passes before pushing code. You can use `yarn lint` and `yarn lint:fix` inside the packages' folders.
+The linter is always run in the CI, so make sure it passes before pushing code. You can use `pnpm lint` and `pnpm lint:fix` inside the packages' folders.
 
 ## Branching
 
@@ -95,23 +95,17 @@ This is a list of the modules that always get loaded during startup:
 
 ## Developing locally
 
-All these tips assume you are running `yarn watch` from the root directory.
+All these tips assume you are running `pnpm watch` from the root directory.
 
 ### Linking
 
-You can [link](https://classic.yarnpkg.com/en/docs/cli/link/) any package to test it locally. While the rest of the commands we run use `yarn`, we recommend you use `npm` for linking, since `yarn link` won't create the `hardhat` executable. For example, if you are working on `hardhat`, you can follow these steps:
+You can [link](https://docs.npmjs.com/cli/v9/commands/npm-link/) any package to test it locally. While the rest of the commands we run use `pnpm`, we recommend you use `npm` for linking. For example, if you are working on `hardhat`, you can follow these steps:
 
 1. Go to `packages/hardhat-core` and run `npm link`
 2. Go to some hardhat project and run `npm link hardhat`
 
 Now any change you make in the code will be reflected in that project.
 
-If you prefer to use `yarn link`, you need to work around the lack of an executable in `node_modules/.bin/hardhat`. We recommend having an alias like this:
-
-```bash
-alias lhh='node --preserve-symlinks $(node -e "console.log(require.resolve(\"hardhat/internal/cli/cli.js\"))")'
-```
-
 ### Yalc
 
 If for any reason linking doesn't work for you, you can use [`yalc`](https://github.com/whitecolor/yalc):
@@ -121,12 +115,12 @@ If for any reason linking doesn't work for you, you can use [`yalc`](https://git
 
 Unlike linking, if you make a change in the code, you'll need to repeat the process.
 
-### yarn pack
+### pnpm pack
 
-An even more realistic way of using your local changes in a project is to use [`yarn pack`](https://classic.yarnpkg.com/en/docs/cli/pack/):
+An even more realistic way of using your local changes in a project is to use [`pnpm pack`](https://pnpm.io/cli/pack):
 
-1. Go to `packages/hardhat-core` and run `yarn pack`. This will create a `nomiclabs-hardhat-x.y.z.tgz` file in that directory.
-2. Go to some hardhat project and run `yarn add /path/to/hardhat/packages/hardhat/nomiclabs-hardhat-x.y.z.tgz`.
+1. Go to `packages/hardhat-core` and run `pnpm pack`. This will create a `nomiclabs-hardhat-x.y.z.tgz` file in that directory.
+2. Go to some hardhat project and run `npm install /path/to/hardhat/packages/hardhat/nomiclabs-hardhat-x.y.z.tgz`.
 
 Unlike linking, if you make a change in the code, you'll need to repeat the process.