fix: code coverage reporting

Author: evansims

.github/workflows/main.yaml

@@ -27,7 +27,7 @@ jobs:
         run: dotnet build --no-restore
 
       - name: Test
-        run: dotnet test --no-build --verbosity normal --collect "Code Coverage"
+        run: dotnet test --no-build --verbosity normal /p:CollectCoverage=true /p:CoverletOutputFormat=opencover
 
       - uses: actions/upload-artifact@26f96dfa697d77e81fd5907df203aa23a56210a8 #v4.3.1
         with: