bump the Go compiler version to 1.13 for circle CI (pingcap#12557)

tiancaiamao · web-flow · commit 8392e1be6b15 · 2019-10-09T14:41:56.000+08:00
diff --git a/circle.yml b/circle.yml
@@ -3,10 +3,10 @@ version: 2
 jobs:
   build:
     docker:
-      - image: golang:1.12
+      - image: golang:1.13
     working_directory: /go/src/github.com/pingcap/tidb
     steps:
       - checkout
       - run:
           name: "Build & Test"
-          command: make dev
+          command: make dev
