Upgrade fsdoc to fix missing documentation toc (#536)

Author: wallymathieu

.config/dotnet-tools.json

@@ -9,7 +9,7 @@
       ]
     },
     "fsdocs-tool": {
-      "version": "16.1.1",
+      "version": "17.2.3",
       "commands": [
         "fsdocs"
       ]

.github/workflows/fable.yml

@@ -17,12 +17,12 @@ jobs:
       run: git submodule update --init --recursive
     - name: Remove global json
       run: rm global.json
-    - name: Setup .NET Core
+    - name: Setup .NET Core 6
       uses: actions/setup-dotnet@v1
       with:
         dotnet-version: 6.0.201
     - name: Restore tools
-      run: dotnet tool restore
+      run: dotnet tool install --global Fable --version 3.7.20
     - name: Use Node.js
       uses: actions/setup-node@v1
       with: