Bump actions/setup-dotnet from 4 to 5 (#322)

Author: vcsjones

.github/workflows/pr.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
       name: Checkout
-    - uses: actions/setup-dotnet@v4
+    - uses: actions/setup-dotnet@v5
       with:
         dotnet-version: '8.0'
     - run: dotnet test