How to fix a R1Soft NO_PUBKEY error during apt-get update

During a recent apt-get update of one of our systems, we encountered an error with the R1Soft repository for CDP:

W: GPG error: http://repo.r1soft.com stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1BF3530AA40384ED

It appears that R1Soft started using a new key which they publish.  In order to get this repository working again, you must update to use the new key.  Use the following commands to import the new key:

wget http://repo.r1soft.com/r1soft.asc
apt-key add r1soft.asc
apt-get update

The key (pun intendned) of this post is to remind myself of the URL of the public key block.