Bump doctrine/instantiator from 1.0.5 to 1.5.0

Bumps [doctrine/instantiator](https://github.com/doctrine/instantiator) from 1.0.5 to 1.5.0.
- [Release notes](https://github.com/doctrine/instantiator/releases)
- [Commits](doctrine/instantiator@1.0.5...1.5.0)

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

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

composer.json

@@ -22,7 +22,7 @@
         }
     },
     "require-dev": {
-        "doctrine/instantiator": "~1.0.5",
+        "doctrine/instantiator": "~1.5.0",
         "fzaninotto/faker": "^1.8",
         "nanasess/ec-cube2-class-extends-stubs": "^1.0",
         "nanasess/eccube2-fixture-generator": "^1.2",