Update concurrent-ruby to version 1.3.5

Author: depfu[bot]

Gemfile.lock

@@ -45,7 +45,7 @@ GEM
     codecov (0.6.0)
       simplecov (>= 0.15, < 0.22)
     coderay (1.1.3)
-    concurrent-ruby (1.2.3)
+    concurrent-ruby (1.3.5)
     connection_pool (2.4.1)
     diff-lcs (1.5.0)
     docile (1.4.0)