Docs: Update bid-adapter-porting-guide.md (prebid#3820)

Co-authored-by: Oleksandr Zhevedenko <720803+Net-burst@users.noreply.github.com>

Author: bretg

docs/developers/bid-adapter-porting-guide.md

@@ -69,4 +69,4 @@ To maintain consistency across adapters:
     - Blocking code.
     - Fully dynamic hostnames in URLs.
     - Non-thread-safe code (bidder adapters should not store state internally).
-6. If an adapter has no special logic, consider using an alias to `Generic` instead.
+6. If an adapter has no special logic, consider using an alias to `Generic` instead. In this case, there will still need to be an integration test for this bidder. e.g. `src/test/java/org/prebid/server/it/BidderNameTest.java`