build(deps-dev): bump phpspec/prophecy from 1.14.0 to 1.15.0 (#134)

Bumps [phpspec/prophecy](https://github.com/phpspec/prophecy) from 1.14.0 to 1.15.0.
- [Release notes](https://github.com/phpspec/prophecy/releases)
- [Changelog](https://github.com/phpspec/prophecy/blob/master/CHANGES.md)
- [Commits](phpspec/prophecy@1.14.0...v1.15.0)

---
updated-dependencies:
- dependency-name: phpspec/prophecy
  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

@@ -25,7 +25,7 @@
         "http-interop/http-factory-guzzle": "^1.2",
         "infection/infection": "^0.11.5",
         "php-http/mock-client": "^1.1",
-        "phpspec/prophecy": "~1.14",
+        "phpspec/prophecy": "~1.15",
         "phpstan/phpstan": "^1.0",
         "phpunit/phpunit": "^8"
     },