Update composer.json

symfony/debug was not mentioned in the replace list
merged branch sstok/patch-6 (PR #7723)

This PR was merged into the master branch.

Discussion
----------

Update composer.json (symfony/debug was not mentioned in the replace list)

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

symfony/debug was not mentioned in the replace list

Commits
-------

57d476b Update composer.json