Added line to the changelog.
- MAST: Added convenience function to list available missions. [#947]
- SIMBAD: adding 'get_query_payload' kwarg to all public methods to return
the request parameters. [#962]
+- CosmoSim: Fixed login service. [#999]
- ESO: The upstream API changed. We have adapted. [#970]
- ESO: Added 'destination' keyword to Eso.retrieve_data(), to download files
to a specific location (other than the cache). [#976]
