Update mattermost library (#2152)

* Update mattermost library

* Fix linting

vendor/github.com/hashicorp/go-hclog/global.go

@@ -0,0 +1,67 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MIT
+
+package hclog
+
+import (
+	"sync"
+	"time"
+)
+
+var (
+	protect sync.Once
+	def     Logger
+
+	// DefaultOptions is used to create the Default logger. These are read
+	// only when the Default logger is created, so set them as soon as the
+	// process starts.
+	DefaultOptions = &LoggerOptions{
+		Level:  DefaultLevel,
+		Output: DefaultOutput,
+		TimeFn: time.Now,
+	}
+)
+
+// Default returns a globally held logger. This can be a good starting
+// place, and then you can use .With() and .Named() to create sub-loggers
+// to be used in more specific contexts.
+// The value of the Default logger can be set via SetDefault() or by
+// changing the options in DefaultOptions.
+//
+// This method is goroutine safe, returning a global from memory, but
+// care should be used if SetDefault() is called it random times
+// in the program as that may result in race conditions and an unexpected
+// Logger being returned.
+func Default() Logger {
+	protect.Do(func() {
+		// If SetDefault was used before Default() was called, we need to
+		// detect that here.
+		if def == nil {
+			def = New(DefaultOptions)
+		}
+	})
+
+	return def
+}
+
+// L is a short alias for Default().
+func L() Logger {
+	return Default()
+}
+
+// SetDefault changes the logger to be returned by Default()and L()
+// to the one given. This allows packages to use the default logger
+// and have higher level packages change it to match the execution
+// environment. It returns any old default if there is one.
+//
+// NOTE: This is expected to be called early in the program to setup
+// a default logger. As such, it does not attempt to make itself
+// not racy with regard to the value of the default logger. Ergo
+// if it is called in goroutines, you may experience race conditions
+// with other goroutines retrieving the default logger. Basically,
+// don't do that.
+func SetDefault(log Logger) Logger {
+	old := def
+	def = log
+	return old
+}