chore(security): patch rake vulnerability (#347)

Author: dependabot[bot]

Gemfile.lock

@@ -117,7 +117,7 @@ GEM
       activesupport (= 4.2.7.1)
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
-    rake (12.3.0)
+    rake (13.0.1)
     rotp (3.1.0)
     rspec-core (3.8.0)
       rspec-support (~> 3.8.0)