Update build scripts to use .NET 9 SDK

Author: runegulbrandsen

.github/workflows/master-pr.yml

@@ -22,10 +22,10 @@ jobs:
     steps:
     - name: Checkout source
       uses: actions/checkout@v4
-    - name: Setup .NET 8.0.x
+    - name: Setup .NET 9.0.x
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
     - name: Restore solution
       run: dotnet restore
     - name: Build solution

.github/workflows/master-publish.yml

@@ -16,10 +16,10 @@ jobs:
         echo "VERSION=${VERSION#v}" >> $GITHUB_ENV
     - name: Checkout source
       uses: actions/checkout@v4
-    - name: Setup .NET 8.0.x
+    - name: Setup .NET 9.0.x
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
     - name: Restore solution
       run: dotnet restore
     - name: Build solution (pre-release)

.github/workflows/master-push.yml

@@ -19,10 +19,10 @@ jobs:
     steps:
     - name: Checkout source
       uses: actions/checkout@v4
-    - name: Setup .NET 8.0.x
+    - name: Setup .NET 9.0.x
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
     - name: Restore solution
       run: dotnet restore
     - name: Build solution