MM-28737: Upgrade dependencies (#15877)

https://mattermost.atlassian.net/browse/MM-28737

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

vendor/github.com/couchbase/vellum/README.md

@@ -1,6 +1,6 @@
 # ![vellum](docs/logo.png) vellum
 
-[![Build Status](https://travis-ci.org/couchbase/vellum.svg?branch=master)](https://travis-ci.org/couchbase/vellum)
+[![Tests](https://github.com/couchbase/vellum/workflows/Tests/badge.svg?branch=master&event=push)](https://github.com/couchbase/vellum/actions?query=workflow%3ATests+event%3Apush+branch%3Amaster)
 [![Coverage Status](https://coveralls.io/repos/github/couchbase/vellum/badge.svg?branch=master)](https://coveralls.io/github/couchbase/vellum?branch=master)
 [![GoDoc](https://godoc.org/github.com/couchbase/vellum?status.svg)](https://godoc.org/github.com/couchbase/vellum)
 [![Go Report Card](https://goreportcard.com/badge/github.com/couchbase/vellum)](https://goreportcard.com/report/github.com/couchbase/vellum)

vendor/github.com/couchbase/vellum/fst_iterator.go

@@ -265,7 +265,7 @@ OUTER:
 		// going back all the way to the OUTER loop
 		var popNum int
 		for j := len(i.statesStack) - 1; j > 0; j-- {
-			if i.statesStack[j].NumTransitions() != 1 {
+			if j == 1 || i.statesStack[j].NumTransitions() != 1 {
 				popNum = len(i.statesStack) - 1 - j
 				break
 			}