textproc/pecl-zephir_parser: Update 1.6.0 => 1.8.0

Changelogs:
https://github.com/zephir-lang/php-zephir-parser/releases/tag/v1.6.1
https://github.com/zephir-lang/php-zephir-parser/releases/tag/v1.7.0
https://github.com/zephir-lang/php-zephir-parser/releases/tag/v1.8.0

PR: 293619
Approved by: R. Christian McDonald <rcm@rcm.sh> (maintainer, timeout 2 weeks)