Version 0.3.0 of Swiftly the swift toolchain installer has been released.
The key new feature in v0.3.0 is toolchain PGP verification. Swiftly will now verify the PGP key of your downloaded toolchain before installing it.
Version 0.2.0 did introduce a self-update command, but unfortunately it was broken. This has now been fixed. Because of this plus the fact that the install script installs the required PGP keys, you will need to run the install script again.