Errors - spaceshiptrip/raspberrypi GitHub Wiki

pi@martin-pi:~ $ sudo apt update
Get:1 https://dl.yarnpkg.com/debian stable InRelease [17.1 kB]
Get:2 http://packages.microsoft.com/repos/code stable InRelease [10.4 kB]      
Hit:3 https://download.docker.com/linux/raspbian buster InRelease              
Get:4 http://archive.raspberrypi.org/debian buster InRelease [32.8 kB]         
Get:5 https://deb.nodesource.com/node_15.x buster InRelease [4,584 B]          
Get:7 http://raspbian.raspberrypi.org/raspbian buster InRelease [15.0 kB]      
Get:8 http://packages.microsoft.com/repos/code stable/main amd64 Packages [13.9 kB]
Get:9 http://packages.microsoft.com/repos/code stable/main arm64 Packages [14.5 kB]
Get:10 http://packages.microsoft.com/repos/code stable/main armhf Packages [14.3 kB]
Get:11 https://deb.nodesource.com/node_15.x buster/main armhf Packages [777 B] 
Hit:6 https://packagecloud.io/headmelted/codebuilds/debian stretch InRelease   
Get:12 http://raspbian.raspberrypi.org/raspbian buster/main armhf Packages [13.0 MB]
Get:13 http://archive.raspberrypi.org/debian buster/main armhf Packages [364 kB]
Err:6 https://packagecloud.io/headmelted/codebuilds/debian stretch InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0CC3FD642696BFC8
Fetched 13.5 MB in 33s (405 kB/s)                                              
Reading package lists... Done
Building dependency tree       
Reading state information... Done
17 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://packagecloud.io/headmelted/codebuilds/debian stretch InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0CC3FD642696BFC8
W: Failed to fetch https://packagecloud.io/headmelted/codebuilds/debian/dists/stretch/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0CC3FD642696BFC8
W: Some index files failed to download. They have been ignored, or old ones used instead.