Fixes #4893: Added note about `cookieValidationKey` and console application to UPGRADE Added note to config change
Fixes #4893: Added note about `cookieValidationKey` and console application to UPGRADE
Added note to config change

To get rid of confusions and errors. related to https://github.com/yiisoft/yii2/issues/4893

yiisoft/yii2-framework,yiisoft/yii2-framework