What about saving bookmark in your browser to a commit that contains it?
It's not because of me personally - I can of course copy-out the file, have it printed on a hand-made paper, have it leather-bound and read it every day before going to bed. But I think everyone should have an easy access to the file - it describes the history of Geany (and not all of the information is in the commits - e.g. the first few releases of Geany weren't version-controlled) and the same way we wouldn't remove old commits from the git repository, we shouldn't remove the changelog file IMO.
I'm saying this just because I don't want to make the change myself as I don't find it right. But feel free to create a separate pull request that removes the file - I'm definitely not going to block its merging if others think it should be removed.