chore(release): Changelog for 20.0.0-rc.1

[nickvergessen]

20.0.0-rc.1 – 2024-08-15

Fixed

• Show upcoming event information (up to 1 month) in conversation top bar #12984

Fixed

• Show user status messages of other local users in a federated conversation #12982
• Don't trigger notifications for system messages in federated conversations #12985
• Add a quick option to log-in when visiting a public conversation as a guest #12988
• Save displayname immediately when inviting a federated account #12954
• Show error messages when uploading a file failed #12919
• Add a hint how to add federated accounts #12916
• Retain order of attachments when uploading multiple #12904
• Don't allow to enable bots in former one-to-one conversations #12893
• Hide ban option for federated accounts as they are not supported for now #12980
• Various design fixes