Switch PHP CS Fixer to PER-CS 3.0

[dbuhonov]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	#430

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 76.96%. Comparing base (71d3a0f) to head (ff20e9e).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Environment.php	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #454   +/-   ##
=========================================
  Coverage     76.96%   76.96%           
  Complexity       29       29           
=========================================
  Files            11       11           
  Lines           178      178           
=========================================
  Hits            137      137           
  Misses           41       41           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[vjik]

Add line to changelog

[vjik]

@dbuhonov Thank you!