Last middleware should use the request passed by preceding middleware. (#965)

This is useful when preceding middleware reads httpRequest.Body to
perform some logic, and assigns a new ReadCloser to httpRequest.Body
(as body can be read only once).

api/server/middleware.go

@@ -93,7 +93,7 @@ func (s *Server) runMiddleware(c *gin.Context, ms []fnext.Middleware) {
 			c.Abort()
 			return
 		}
-		c.Request = c.Request.WithContext(ctx)
+		c.Request = r.WithContext(ctx)
 		c.Next()
 	})