replace all instances of yarn in docusaurus with pnpm

apps/docs/README-docusaurus.md

@@ -5,16 +5,16 @@ This website is built using [Docusaurus 2](https://docusaurus.io/), a modern sta
 ### Installation
 
 ```
-$ yarn
+$ pnpm
 ```
 
 ### Local Development
 
 ```
-$ yarn start
+$ pnpm start
 ```
 
-This command starts a local development server and opens up a browser window. Most changes are reflected live without having to restart the server. 
+This command starts a local development server and opens up a browser window. Most changes are reflected live without having to restart the server.
 
 However, the searchbar may not function with `yarn start`. Instead, run `yarn build` and launch a server:
 
@@ -25,7 +25,7 @@ $ npx http-server ./build
 ### Build
 
 ```
-$ yarn build
+$ pnpm build
 ```
 
 This command generates static content into the `build` directory and can be served using any static contents hosting service.
@@ -35,13 +35,13 @@ This command generates static content into the `build` directory and can be serv
 Using SSH:
 
 ```
-$ USE_SSH=true yarn deploy
+$ USE_SSH=true pnpm deploy
 ```
 
 Not using SSH:
 
 ```
-$ GIT_USER=<Your GitHub username> yarn deploy
+$ GIT_USER=<Your GitHub username> pnpm deploy
 ```
 
 If you are using GitHub pages for hosting, this command is a convenient way to build the website and push to the `gh-pages` branch.