Update .NET SDK version to 9.0.0 in global.json

Updated the `sdk` version in the `global.json` file from `7.0.0` to `9.0.0` to target the newer .NET SDK version. This change ensures the project uses the latest features, improvements, and fixes available in .NET SDK 9.0.0. The `rollForward` setting remains `latestMajor`, and `allowPrerelease` is still set to `false`.

Author: Jack251970

.github/workflows/build.yml

@@ -36,7 +36,7 @@ jobs:
         uses: actions/setup-dotnet@v5
         with:
           dotnet-version: |
-            7.0.x
+            9.0.x
 
       # Restore dependencies
       - name: Restore dependencies

.github/workflows/publish.yml

@@ -30,7 +30,7 @@ jobs:
         uses: actions/setup-dotnet@v5
         with:
           dotnet-version: |
-            7.0.x
+            9.0.x
 
       # Restore dependencies
       - name: Restore dependencies

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "7.0.0",
+    "version": "9.0.0",
     "rollForward": "latestMajor",
     "allowPrerelease": false
   }