Installing Spotify via the Software Boutique succeds after importing a different gpg key

[ghost]

Ubuntu MATE version: 21.10

Steps to Reproduce:

1. Install Ubuntu MATE 21.10
2. Install Spotify via the Software Boutique

Installing Spotify graphically via the "Software Boutique" failed (with an error message I can't recollect). I then ran sudo apt update which returned a GPG error saying:

http://repository.spotify.com stable InRelease is not signed. Updating from such a repository can't be done securely and is therefore disabled by default

The installation succeeded after running curl -sS https://download.spotify.com/debian/pubkey_5E3C45D7B312C643.gpg | sudo apt-key add - in a terminal as per Spotify's instructions on their website and trying to install Spotify via the Software Boutique a second time.

I did some scouring around the source code in this repo and I think the listed key in metadata.json for Spotify is a different key (D2C19886), could this potentially need updating?

I would love to open a pull request for review if that is the case!