Migrate to go mod and go 1.13 (#29)

* Add missed go mod

.travis.yml

@@ -23,6 +23,8 @@ before_script:
 # in a modern Go project.
 script:
   - test -z $(gofmt -s -l $GO_FILES) # Fail if a .go file hasn't been formatted with gofmt
+  - go test -v -race ./... # Run all the tests with the race detector enabled
+  - go vet ./... # go vet is the official Go static analyzer
   - gocyclo -over 19 cmd pkg # forbid code with huge/complex functions
   - golint -set_exit_status $(go list ./...) # one last linter
-  - GO111MODULE=on go build cmd/helm-gcs/main.go # compilation
+  - go build cmd/helm-gcs/main.go # compilation

go.mod

@@ -0,0 +1,18 @@
+module github.com/hayorov/helm-gcs
+
+go 1.13
+
+require (
+	cloud.google.com/go/storage v1.0.0
+	github.com/Masterminds/semver v1.5.0 // indirect
+	github.com/cyphar/filepath-securejoin v0.2.2 // indirect
+	github.com/ghodss/yaml v1.0.0
+	github.com/gobwas/glob v0.2.3 // indirect
+	github.com/pkg/errors v0.8.1
+	github.com/sirupsen/logrus v1.4.2
+	github.com/spf13/cobra v0.0.5
+	google.golang.org/api v0.11.1-0.20191026000714-8038894d941c
+	k8s.io/apimachinery v0.0.0-20191025225532-af6325b3a843 // indirect
+	k8s.io/client-go v11.0.0+incompatible // indirect
+	k8s.io/helm v2.15.1+incompatible
+)