Add changelog for 252
This MR was automatically created from CI, https://gitlab.com/gitlab-org/gitter/gitter-android-app/-/jobs/137393189
We copied CURRENT_VERSION.txt
-> 252.txt
This MR was automatically created from CI, https://gitlab.com/gitlab-org/gitter/gitter-android-app/-/jobs/137393189
We copied CURRENT_VERSION.txt
-> 252.txt