ci: add index.md when autogenerating README.md (#518)

Author: sindharta

.github/workflows/update-readme.yml

@@ -28,6 +28,11 @@ jobs:
       - name: Read Documentation Index
         id: read-doc-index
         uses: unity3d-jp/actions/read-file@main
+        with:
+          filepath: 'com.unity.toonshader/Documentation~/index.md'
+      - name: Read Documentation TOC
+        id: read-doc-toc
+        uses: unity3d-jp/actions/read-file@main
         with:
           filepath: 'com.unity.toonshader/Documentation~/TableOfContents.md'
       - name: Overwrite Readme with Index
@@ -56,6 +61,10 @@ jobs:
           cat temp.md >> $generated_file
           rm temp.md
 
+          cat <<"EOF" >> $generated_file
+          ${{ steps.read-doc-toc.outputs.content }}
+          EOF
+
           cat <<"EOF" >> $generated_file
           ${{ steps.read-footer.outputs.content }}
           EOF

AutoGenerateParts/ReadmeHeader.md

@@ -2,5 +2,4 @@
 - [English](https://docs.unity3d.com/Packages/com.unity.toonshader@latest)
 - [日本語](https://docs.unity3d.com/ja/Packages/com.unity.toonshader@latest)
 
-# Unity Toon Shader