Added missing .net 9 setup in pack and publish (#6)

Author: adamthewilliam

.github/workflows/pack-and-publish.yml

@@ -51,11 +51,17 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+    
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
         dotnet-version: 8.0.x
 
+    - name: Setup .NET 9.0
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: 9.0.x
+
     - name: Restore dependencies
       run: dotnet restore src/Hooki