Updated .NET version to a newer version

Author: Morten Turn Pedersen

.github/workflows/pullrequest.yml

@@ -13,13 +13,17 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 3.1.101
+        dotnet-version: 3.1.301
+
     - name: Install dependencies
       run: dotnet restore
+
     - name: Build
       run: dotnet build --configuration Release --no-restore
+
     - name: Test
       run: dotnet test --no-restore --verbosity normal