Update mattermost library (#2152)

* Update mattermost library

* Fix linting

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

@@ -0,0 +1,85 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MIT
+
+package hclog
+
+import (
+	"bytes"
+	"io"
+)
+
+type writer struct {
+	b     bytes.Buffer
+	w     io.Writer
+	color ColorOption
+}
+
+func newWriter(w io.Writer, color ColorOption) *writer {
+	return &writer{w: w, color: color}
+}
+
+func (w *writer) Flush(level Level) (err error) {
+	var unwritten = w.b.Bytes()
+
+	if w.color != ColorOff {
+		color := _levelToColor[level]
+		unwritten = []byte(color.Sprintf("%s", unwritten))
+	}
+
+	if lw, ok := w.w.(LevelWriter); ok {
+		_, err = lw.LevelWrite(level, unwritten)
+	} else {
+		_, err = w.w.Write(unwritten)
+	}
+	w.b.Reset()
+	return err
+}
+
+func (w *writer) Write(p []byte) (int, error) {
+	return w.b.Write(p)
+}
+
+func (w *writer) WriteByte(c byte) error {
+	return w.b.WriteByte(c)
+}
+
+func (w *writer) WriteString(s string) (int, error) {
+	return w.b.WriteString(s)
+}
+
+// LevelWriter is the interface that wraps the LevelWrite method.
+type LevelWriter interface {
+	LevelWrite(level Level, p []byte) (n int, err error)
+}
+
+// LeveledWriter writes all log messages to the standard writer,
+// except for log levels that are defined in the overrides map.
+type LeveledWriter struct {
+	standard  io.Writer
+	overrides map[Level]io.Writer
+}
+
+// NewLeveledWriter returns an initialized LeveledWriter.
+//
+// standard will be used as the default writer for all log levels,
+// except for log levels that are defined in the overrides map.
+func NewLeveledWriter(standard io.Writer, overrides map[Level]io.Writer) *LeveledWriter {
+	return &LeveledWriter{
+		standard:  standard,
+		overrides: overrides,
+	}
+}
+
+// Write implements io.Writer.
+func (lw *LeveledWriter) Write(p []byte) (int, error) {
+	return lw.standard.Write(p)
+}
+
+// LevelWrite implements LevelWriter.
+func (lw *LeveledWriter) LevelWrite(level Level, p []byte) (int, error) {
+	w, ok := lw.overrides[level]
+	if !ok {
+		w = lw.standard
+	}
+	return w.Write(p)
+}