chore(deps): cleanup go.mod a little bit (#136)

* Upgrade docker to v19.03.7

* go mod vendor

* golangci-lint 1.23.8

vendor/github.com/google/go-cmp/cmp/export_panic.go

@@ -0,0 +1,15 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// +build purego
+
+package cmp
+
+import "reflect"
+
+const supportAllowUnexported = false
+
+func retrieveUnexportedField(reflect.Value, reflect.StructField) reflect.Value {
+	panic("retrieveUnexportedField is not implemented")
+}