Adapt to last changes in validator

[vjik]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	-

[what-the-diff[bot]]

• The namespace of the RuleHandlerContainer was changed from Yiisoft\Validator\RuleHandlerContainer to Yiisoft\Validator\RuleHandlerResolverInterface. This is because in version 2.0, the class name has been renamed and moved into a new directory called "rule-handler-resolver".
• In addition, there are two files that have this change: blog/config/common/validator.php and blog-api/config/common/validator.php which means that both projects need to be updated with these changes for them to work properly together when they're deployed on production servers (or any other environment).