minor symfony#23353 [Stopwatch] add changelog entry for Stopwatch::reset() (xabbuh)

This PR was merged into the 3.4 branch.

Discussion
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[Stopwatch] add changelog entry for Stopwatch::reset()

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
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f3867e6 add changelog entry for Stopwatch::reset()

Author: fabpot

src/Symfony/Component/Stopwatch/CHANGELOG.md

@@ -0,0 +1,7 @@
+CHANGELOG
+=========
+
+3.4.0
+-----
+
+ * added the `Stopwatch::reset()` method