minor #31443 [Doctrine\Bridge] fix tests (nicolas-grekas)

This PR was merged into the 4.3 branch.

Discussion
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[Doctrine\Bridge] fix tests

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Once merged, one issue will remain, which will be fixed by https://github.com/doctrine/dbal/pull/3543

Commits
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10da2310da [Doctrine\Bridge] fix tests

src/Symfony/Bridge/Doctrine/composer.json

@@ -25,6 +25,7 @@
     },
     "require-dev": {
         "symfony/stopwatch": "~3.4|~4.0",
+        "symfony/config": "^4.2",
         "symfony/dependency-injection": "~3.4|~4.0",
         "symfony/form": "~4.3",
         "symfony/http-kernel": "~3.4|~4.0",