Make an artifact from failed files on failure

.github/workflows/tests.yaml

@@ -45,6 +45,13 @@ jobs:
       - name: Test
         run: dotnet test --no-restore --filter "Category!=FlakeyNetwork"
         
+      - name: Upload Test Folder on Failure
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@v2
+        with:
+          name: Failed Files
+          path: ./
+  
   publish:
     name: Publish Projects
     runs-on: ubuntu-latest