chore(deps): update dependency dotnet-sdk to v9 (#38)

Author: renovate[bot]

.github/workflows/publish.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.x
+        dotnet-version: 9.x
 
     - name: Restore
       run: dotnet restore src

.github/workflows/test.yml

@@ -27,7 +27,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.x
+        dotnet-version: 9.x
 
     - name: Restore
       run: dotnet restore src

global.json

@@ -1,6 +1,6 @@
 {
     "sdk": {
-        "version": "8.0.403",
+        "version": "9.0.100",
         "rollForward": "latestFeature"
     }
 }