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

* Upgrade docker to v19.03.7

* go mod vendor

* golangci-lint 1.23.8

vendor/golang.org/x/sys/cpu/cpu_riscv64.go

@@ -0,0 +1,9 @@
+// Copyright 2019 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 file.
+
+// +build riscv64
+
+package cpu
+
+const cacheLineSize = 32