*: bump golang to 1.13.4

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

.travis.yml

@@ -8,7 +8,7 @@ services:
   - docker
 
 go:
-  - 1.12.1
+  - 1.13.4
 
 env:
   - GO111MODULE=on DOCKER_CLI_EXPERIMENTAL=enabled

Makefile

@@ -33,7 +33,7 @@ LISTER_GEN_BINARY := bin/lister-gen
 OPENAPI_GEN_BINARY := bin/openapi-gen
 GOLINT_BINARY := bin/golint
 
-BUILD_IMAGE ?= golang:1.12.1-alpine
+BUILD_IMAGE ?= golang:1.13.4-alpine
 
 build: $(BINS)
 

go.mod

@@ -60,3 +60,5 @@ require (
 	k8s.io/utils v0.0.0-20190308190857-21c4ce38f2a7 // indirect
 	sigs.k8s.io/yaml v1.1.0 // indirect
 )
+
+go 1.13