rebase: vendor dependencies for Vault API

Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.

By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/google.golang.org/protobuf/internal/pragma/pragma.go

@@ -0,0 +1,29 @@
+// Copyright 2018 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.
+
+// Package pragma provides types that can be embedded into a struct to
+// statically enforce or prevent certain language properties.
+package pragma
+
+import "sync"
+
+// NoUnkeyedLiterals can be embedded in a struct to prevent unkeyed literals.
+type NoUnkeyedLiterals struct{}
+
+// DoNotImplement can be embedded in an interface to prevent trivial
+// implementations of the interface.
+//
+// This is useful to prevent unauthorized implementations of an interface
+// so that it can be extended in the future for any protobuf language changes.
+type DoNotImplement interface{ ProtoInternal(DoNotImplement) }
+
+// DoNotCompare can be embedded in a struct to prevent comparability.
+type DoNotCompare [0]func()
+
+// DoNotCopy can be embedded in a struct to help prevent shallow copies.
+// This does not rely on a Go language feature, but rather a special case
+// within the vet checker.
+//
+// See https://golang.org/issues/8005.
+type DoNotCopy [0]sync.Mutex