ci: use pcntl package

Exit code (#238)

* maintenance: dependabot
closes #205

* feature: exit code, closes #236

* test: fix phpstan

* test: improve stream checking

* ci: match phpunit version

fix: deprecation notices & type safety (#157)

Bump phpstan/phpstan from 0.12.84 to 0.12.89 (#116)

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 0.12.84 to 0.12.89.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Commits](phpstan/phpstan@0.12.84...0.12.89)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bump phpstan/phpstan from 0.12.75 to 0.12.76 (#97)

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 0.12.75 to 0.12.76.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Commits](phpstan/phpstan@0.12.75...0.12.76)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Upgrade to PHP 7.4 (#51)

Remove dev-master constraint from Composer

Fix #35 - do not load secondary arguments into value of primary

Merge remote-tracking branch 'origin/master'

Set default argument value correctly