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/go.uber.org/zap/buffer/buffer.go

@@ -23,10 +23,7 @@
 // package's zero-allocation formatters.
 package buffer // import "go.uber.org/zap/buffer"
 
-import (
-	"strconv"
-	"time"
-)
+import "strconv"
 
 const _size = 1024 // by default, create 1 KiB buffers
 
@@ -52,11 +49,6 @@ func (b *Buffer) AppendInt(i int64) {
 	b.bs = strconv.AppendInt(b.bs, i, 10)
 }
 
-// AppendTime appends the time formatted using the specified layout.
-func (b *Buffer) AppendTime(t time.Time, layout string) {
-	b.bs = t.AppendFormat(b.bs, layout)
-}
-
 // AppendUint appends an unsigned integer to the underlying buffer (assuming
 // base 10).
 func (b *Buffer) AppendUint(i uint64) {