[DEPS]: Bump composer/composer from 2.0.13 to 2.1.6

Bumps [composer/composer](https://github.com/composer/composer) from 2.0.13 to 2.1.6.
- [Release notes](https://github.com/composer/composer/releases)
- [Changelog](https://github.com/composer/composer/blob/master/CHANGELOG.md)
- [Commits](composer/composer@2.0.13...2.1.6)

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

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