Update PHPStan

[gomzyakov]

When we run phpstan analyze, we looked a message:

⚠️  You're running a really old version of PHPStan.️

The last release in the 0.12.x series with new features
and bugfixes was released on September 12th 2021,
that's 582 days ago.

Since then more than 67 new PHPStan versions were released
with hundreds of new features, bugfixes, and other
quality of life improvements.

To learn about what you're missing out on, check out
this blog with articles about the latest major releases:
https://phpstan.org/blog

Upgrade today to PHPStan 1.8 or newer by using
"phpstan/phpstan": "^1.8" in your composer.json.