docs: we use npm, not yarn

README.md

@@ -5,13 +5,13 @@ This website is built using [Docusaurus 2](https://docusaurus.io/), a modern sta
 ## Installation
 
 ```console
-yarn install
+npm install
 ```
 
 ## Local Development
 
 ```console
-yarn start
+npm 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.
@@ -19,19 +19,11 @@ This command starts a local development server and opens up a browser window. Mo
 ## Build
 
 ```console
-yarn build
+npm run build
 ```
 
 This command generates static content into the `build` directory and can be served using any static contents hosting service.
 
-## Deployment
-
-```console
-GIT_USER=<Your GitHub username> USE_SSH=true yarn 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.
-
 ## Create a new page
 
 [Follow this doc](doc/pages.md).