doc: fix changelog date typo

PR-URL: #26831
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>

doc/changelogs/CHANGELOG_V6.md

@@ -78,7 +78,7 @@
 will be supported actively until April 2018 and maintained until April 2019.
 
 <a id="6.17.0"></a>
-## 2018-02-28, Version 6.17.0 'Boron' (LTS), @rvagg
+## 2019-02-28, Version 6.17.0 'Boron' (LTS), @rvagg
 
 This is a security release. All Node.js users should consult the security release summary at: