Fix retype publish by roll foward .NET in pipeline (#39)

* Fix retype publish by installing .NET 7 in pipeline

* roll forward

Author: heqianwang

.github/workflows/publish-docs.yml

@@ -13,13 +13,17 @@ jobs:
 
     permissions:
       contents: write  # to update the retype branch
-    
+
     steps:
       - uses: actions/checkout@v4
 
+      - uses: actions/setup-dotnet@v4
+
       - name: Build with Retype
         uses: retypeapp/action-build@latest
         id: retype
+        env:
+          DOTNET_ROLL_FORWARD: LatestMajor
         with:
           config: docs/retype.yaml
           license: ${{ secrets.RETYPE_API_KEY }}