Add link to real changelog

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

CHANGELOG.md

@@ -1,20 +1,4 @@
-ChangeLog
+Changelog
 =========
 
-NC 11 (2016-12-13)
-------------------
-* PHP 5.4 and 5.5 no longer supported
-* PHP 7.1 support
-* OC_L10N removed use \OCP\IL10N (#1948)
-* Preview handling is improved by sharing previews:
-  * Preview sharing (shared files/external storages)
-  * Previews are stored in the AppData
-  * Previews are served faster by not first converting them to image objects
-* Core preview route changed:
-  * Route for the urlgenerator changed from 'core_ajax_preview' to 'core.Preview.getPreview'
-  * $urlGenerator->linkToRoute('core_ajax_preview', ...) => $urlGenerator->linkToRoute('core.Preview.getPreview', ...)
-* Avatars are cached
-* Avatars are moved to AppData
-  * For existing avatars this happens automatically in a background job which means that on upgrade you might
-    not see your avatar right away. However after the job has run it should show up again automatically.
-
+The change log is at [https://nextcloud.com/changelog/](https://nextcloud.com/changelog/).