fix feature freeze dates
bug #4599 [Contributing] fix feature freeze dates (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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[Contributing] fix feature freeze dates

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #4510

Commits
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8f25a15 fix feature freeze dates