build(deps-dev): bump phpstan/phpstan from 1.3.0 to 1.4.4 (#136)

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.3.0 to 1.4.4.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/master/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.3.0...1.4.4)

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

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

composer.json

@@ -26,7 +26,7 @@
         "infection/infection": "^0.11.5",
         "php-http/mock-client": "^1.1",
         "phpspec/prophecy": "~1.15",
-        "phpstan/phpstan": "^1.3",
+        "phpstan/phpstan": "^1.4",
         "phpunit/phpunit": "^8"
     },
     "config": {