Bump doctrine/orm from 2.14.2 to 2.15.0

Bumps [doctrine/orm](https://github.com/doctrine/orm) from 2.14.2 to 2.15.0.
- [Release notes](https://github.com/doctrine/orm/releases)
- [Commits](doctrine/orm@2.14.2...2.15.0)

---
updated-dependencies:
- dependency-name: doctrine/orm
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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