use go1.14

Author: jirfag

go.mod

@@ -9,7 +9,6 @@ require (
 	github.com/aws/aws-lambda-go v1.11.1
 	github.com/aws/aws-sdk-go v1.28.5
 	github.com/cenkalti/backoff v2.2.1+incompatible
-	github.com/cenkalti/backoff/v4 v4.0.0
 	github.com/certifi/gocertifi v0.0.0-20190506164543-d2eda7129713 // indirect
 	github.com/docker/distribution v2.7.1+incompatible // indirect
 	github.com/docker/docker v1.13.1 // indirect
@@ -68,4 +67,4 @@ require (
 	gopkg.in/yaml.v2 v2.2.4
 )
 
-go 1.13
+go 1.14