Update dependencies and vendor (#1761)

vendor/github.com/mattermost/mattermost-server/v6/model/post_list.go

@@ -5,6 +5,7 @@ package model
 
 import (
 	"encoding/json"
+	"io"
 	"sort"
 )
 
@@ -80,6 +81,11 @@ func (o *PostList) ToJSON() (string, error) {
 	return string(b), err
 }
 
+func (o *PostList) EncodeJSON(w io.Writer) error {
+	o.StripActionIntegrations()
+	return json.NewEncoder(w).Encode(o)
+}
+
 func (o *PostList) MakeNonNil() {
 	if o.Order == nil {
 		o.Order = make([]string, 0)