Bump grape-path-helpers to solve a bug in GrapePathHelpers::NamedRouteMatcher

If you include this helper with a class that also implements `method_missing`,
this would result in AbstractController::DoubleRenderError.

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/19487#note_79096902.

Gemfile.lock

@@ -359,7 +359,7 @@ GEM
     grape-entity (0.7.1)
       activesupport (>= 4.0)
       multi_json (>= 1.3.2)
-    grape-path-helpers (1.0.2)
+    grape-path-helpers (1.0.4)
       activesupport (~> 4)
       grape (~> 1.0)
       rake (~> 12)