docs: Update Docusaurus workflow example (#229)

* Updating Docusaurus config to make it work
* docs: Fix publish_dir

There were some issues, it was impossible to get it working just with a simple copy/paste

* Test repo: https://github.com/peaceiris/test-docusaurus
* Reference: https://docusaurus.io/docs/en/installation

Co-authored-by: peaceiris <[email protected]>

README.md

@@ -678,7 +678,7 @@ jobs:
 
 An example workflow for [Docusaurus](https://docusaurus.io/).
 
-`npx @docusaurus/init@next init` is useful to create a new Docusaurus project.
+`npx @docusaurus/init@next init website classic` is useful to create a new Docusaurus project.
 
 ```yaml
 name: github pages
@@ -712,13 +712,15 @@ jobs:
             ${{ runner.os }}-yarn-
 
       - run: yarn install
+        working-directory: ./website
       - run: yarn build
+        working-directory: ./website
 
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./build
+          publish_dir: ./website/build
 ```
 
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