minor symfony#21898 [github] Add a reminder about CHANGELOG.md files (nicolas-grekas)

This PR was merged into the 2.7 branch.

Discussion
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[github] Add a reminder about CHANGELOG.md files

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Instead of calling for that each time, maybe this can help?

Commits
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cb452ee [github] Add a reminder about CHANGELOG.md files

Author: fabpot

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,10 +1,10 @@
 | Q             | A
 | ------------- | ---
-| Branch?       | master / 2.7, 2.8 or 3.2 <!--see comment below-->
+| Branch?       | master / 2.7, 2.8 or 3.2 <!-- see comment below -->
 | Bug fix?      | yes/no
-| New feature?  | yes/no
+| New feature?  | yes/no <!-- don't forget updating src/**/CHANGELOG.md files -->
 | BC breaks?    | yes/no
-| Deprecations? | yes/no
+| Deprecations? | yes/no <!-- don't forget updating UPGRADE-*.md files -->
 | Tests pass?   | yes/no
 | Fixed tickets | #... <!-- #-prefixed issue number(s), if any -->
 | License       | MIT