We use Developer Certificate of Origin (DCO) introduced by the Linux Foundation. You can find the full transcription of DCO in DeveloperCertificate.org.
To comply with this, you have to sign your commit either with github commit -[-s]ignoff or add a line like this to the bottom of your commit message:
Signed-off-by: Firstname Lastname <address@email.com>
Use your real or preferred name and make sure to stay consistent when signing your commit as possible.