composer(deps): bump doctrine/orm in the doctrine group (#228)

Bumps the doctrine group with 1 update: [doctrine/orm](https://github.com/doctrine/orm).


Updates `doctrine/orm` from 2.20.5 to 2.20.6
- [Release notes](https://github.com/doctrine/orm/releases)
- [Commits](doctrine/orm@2.20.5...2.20.6)

---
updated-dependencies:
- dependency-name: doctrine/orm
  dependency-version: 2.20.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: doctrine
...

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

Author: dependabot[bot]