langs/i18n: Upgrade to go-i18n v2

Fixes #5242

tpl/lang/lang.go

@@ -15,12 +15,13 @@
 package lang
 
 import (
-	"errors"
 	"fmt"
 	"math"
 	"strconv"
 	"strings"
 
+	"github.com/pkg/errors"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/spf13/cast"
 )
@@ -39,12 +40,21 @@ type Namespace struct {
 
 // Translate returns a translated string for id.
 func (ns *Namespace) Translate(id interface{}, args ...interface{}) (string, error) {
+	var templateData interface{}
+
+	if len(args) > 0 {
+		if len(args) > 1 {
+			return "", errors.Errorf("wrong number of arguments, expecting at most 2, got %d", len(args)+1)
+		}
+		templateData = args[0]
+	}
+
 	sid, err := cast.ToStringE(id)
 	if err != nil {
 		return "", nil
 	}
 
-	return ns.deps.Translate(sid, args...), nil
+	return ns.deps.Translate(sid, templateData), nil
 }
 
 // NumFmt formats a number with the given precision using the