chore: upgrade codecov to v0.2.12

Author: shaojunda

Gemfile.lock

@@ -91,7 +91,7 @@ GEM
     builder (3.2.4)
     chronic_duration (0.10.6)
       numerizer (~> 0.1.1)
-    codecov (0.2.8)
+    codecov (0.2.12)
       json
       simplecov
     coderay (1.1.2)
@@ -162,7 +162,7 @@ GEM
     i18n (1.8.5)
       concurrent-ruby (~> 1.0)
     jaro_winkler (1.5.2)
-    json (2.3.1)
+    json (2.4.1)
     kaminari (1.2.1)
       activesupport (>= 4.1.0)
       kaminari-actionview (= 1.2.1)
@@ -310,10 +310,12 @@ GEM
       concurrent-ruby (~> 1.0, >= 1.0.5)
       sidekiq (>= 4.0, < 7.0)
       thor (~> 0)
-    simplecov (0.19.0)
+    simplecov (0.20.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
-    simplecov-html (0.12.2)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.2)
     spring (2.1.0)
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)