Tests: Python 3.7 (PEP 3333) compatibility in uwsgi tests.
diff --git a/uwsgi.t b/uwsgi.t
index b8a3f90..96da7de 100644
--- a/uwsgi.t
+++ b/uwsgi.t
@@ -61,7 +61,7 @@
 
 def application(env, start_response):
     start_response('200 OK', [('Content-Type','text/plain')])
-    return "SEE-THIS"
+    return b"SEE-THIS"
 
 END