Update deprecated download-artifact action to v4 (#44)

Author: seveneleven

.github/workflows/build-and-test.yml

@@ -81,7 +81,7 @@ jobs:
           dotnet-version: ${{ env.dotnet_sdk_version }}
 
       - name: Download package artifacts
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v4
         with:
           name: packages
           path: artifacts/Packages/