Calens changelog updated

Author: abelgardep

CHANGELOG.md

@@ -1,9 +1,9 @@
-Changelog for ownCloud Android Client [unreleased] (UNRELEASED)
+Changelog for ownCloud Android Client [2.18.1] (2021-07-20)
 =======================================
-The following sections list the changes in ownCloud Android Client unreleased relevant to
+The following sections list the changes in ownCloud Android Client 2.18.1 relevant to
 ownCloud admins and users.
 
-[unreleased]: https://github.com/owncloud/android/compare/v2.18.0...master
+[2.18.1]: https://github.com/owncloud/android/compare/v2.18.0...v2.18.1
 
 Summary
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