ERROR:
An error occurred during the signature verification. The repository is not updated and the previous index files will be used.
GPG error: https://dl.yarnpkg.com/debian stable InRelease: The following signatures couldn't be verified because the
public key is not available: NO_PUBKEY 23E7166788B63E1E
SOLUTION:
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -