ci: switches to net9 to get tool formatting capability

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

Author: baywet

.github/workflows/metadata-parser-validation.yml

@@ -33,7 +33,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4.3.1
       with:
-        dotnet-version: 8.x
+        dotnet-version: 9.x
 
     - run: dotnet tool install --global Microsoft.OpenApi.Hidi
       name: Install  Hidi

.github/workflows/openapi-parser-validation.yml

@@ -33,7 +33,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4.3.1
       with:
-        dotnet-version: 8.x
+        dotnet-version: 9.x
 
     - run: dotnet tool install --global Microsoft.OpenApi.Hidi
       name: Install  Hidi