[ksqlDb.RestApi.Client]: github workflows were upgraded to .NET 9

Author: tomasfabian

.github/workflows/dotnet.yml

@@ -11,10 +11,10 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - name: Setup .NET 8.0
+    - name: Setup .NET 9.0
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.x
+        dotnet-version: 9.0.x
 
     - name: Clean
       run: dotnet clean ksqlDb.RestApi.Client.sln --configuration Release && dotnet nuget locals all --clear

.github/workflows/dotnetblazor.yml

@@ -11,10 +11,10 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - name: Setup .NET 8.0
+    - name: Setup .NET 9.0
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.x
+        dotnet-version: 9.0.x
 
     - name: Clean
       run: dotnet clean InsideOut.sln --configuration Release && dotnet nuget locals all --clear