Lock ffi

Author: dmikurube

Gemfile.lock

@@ -38,7 +38,7 @@ GEM
       faraday-net_http (>= 2.0, < 3.1)
       ruby2_keywords (>= 0.0.4)
     faraday-net_http (3.0.2)
-    ffi (1.17.0)
+    ffi (1.15.5)
     forwardable-extended (2.6.0)
     gemoji (4.1.0)
     github-pages (231)