TBR croupier: Fix the Flutter-side tests

Need to clean up packages

Change-Id: Idf17da8e733af33ac2609af0ab260defda33362f
diff --git a/Makefile b/Makefile
index b25dc01..dca4438 100644
--- a/Makefile
+++ b/Makefile
@@ -226,6 +226,7 @@
 endif
 	rm -f croupier.flx snapshot_blob.bin
 	rm -rf bin tmp
+	rm -rf .packages .pub packages pubspec.lock
 
 .PHONY: clean-creds
 clean-creds:
@@ -237,4 +238,3 @@
 
 .PHONY: veryclean
 veryclean: clean clean-creds
-	rm -rf .packages .pub packages pubspec.lock