CI + pre-commit: check PHP syntax, because "Parse error: syntax error" is not allowed

check PHP syntax, because "Parse error: syntax error" is not allowed.

• CI: check PHP syntax
• pre-commit: check PHP syntax

jakub-onderka/php-parallel-lint checks the syntax of PHP files, because "Parse error: syntax error" is not allowed

# install
composer require --dev jakub-onderka/php-parallel-lint

# usage
vendor/bin/parallel-lint ./src/
vendor/bin/parallel-lint ./tests/
vendor/bin/parallel-lint --exclude "vendor" .