Use better name for userinfo structure (#32544)

routers/web/auth/oauth2_provider.go

@@ -82,7 +82,7 @@ func (err errCallback) Error() string {
 type userInfoResponse struct {
 	Sub               string   `json:"sub"`
 	Name              string   `json:"name"`
-	Username string   `json:"preferred_username"`
+	PreferredUsername string   `json:"preferred_username"`
 	Email             string   `json:"email"`
 	Picture           string   `json:"picture"`
 	Groups            []string `json:"groups"`
@@ -99,7 +99,7 @@ func InfoOAuth(ctx *context.Context) {
 	response := &userInfoResponse{
 		Sub:               fmt.Sprint(ctx.Doer.ID),
 		Name:              ctx.Doer.FullName,
-		Username: ctx.Doer.Name,
+		PreferredUsername: ctx.Doer.Name,
 		Email:             ctx.Doer.Email,
 		Picture:           ctx.Doer.AvatarLink(ctx),
 	}