minor #21309 [Serializer] Add missing conflict for property-info<3.1 (chalasr)
minor #21309 [Serializer] Add missing conflict for property-info<3.1 (chalasr)

This PR was merged into the 3.1 branch.

Discussion
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[Serializer] Add missing conflict for property-info<3.1

| Q             | A
| ------------- | ---
| Branch?       | 3.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/pull/21293#discussion_r96254245
| License       | MIT
| Doc PR        | n/a

Commits
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60a0c4b [Serializer] Add missing conflict for property-info<3.1

symfony/serializer,symfony/Serializer