Merge pull request #640 from hidekazuna/bumpgo

🏃 Bump Go to 1.13.15

Author: k8s-ci-robot

Dockerfile

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 # Build the manager binary
-FROM golang:1.13.8 as builder
+FROM golang:1.13.15 as builder
 WORKDIR /workspace
 
 # Run this with docker build --build_arg $(go env GOPROXY) to override the goproxy