9.3 RPMs not signed

Hi, we're receiving the following when updating CentOS 7 hosts to the
9.3.20-3 RPMs:

# yum update postgresql93-libs
...
Dependencies Resolved

================================================================================
Package Arch Version Repository Size
================================================================================
Updating:
postgresql93-libs x86_64 9.3.20-3PGDG.rhel7 pgdg93 205 k
Updating for dependencies:
postgresql93 x86_64 9.3.20-3PGDG.rhel7 pgdg93 1.0 M
postgresql93-contrib x86_64 9.3.20-3PGDG.rhel7 pgdg93 566 k
postgresql93-server x86_64 9.3.20-3PGDG.rhel7 pgdg93 3.7 M

Transaction Summary
================================================================================
Upgrade 1 Package (+3 Dependent packages)

Total size: 5.4 M
Is this ok [y/d/N]: y
Downloading packages:

Package postgresql93-libs-9.3.20-3PGDG.rhel7.x86_64.rpm is not signed

# rpm -qpi /var/cache/yum/x86_64/7/pgdg93/packages/postgresql93-* | grep Sign
Signature : (none)
Signature : (none)
Signature : (none)
Signature : (none)

Please let me know if you need more details.

Thanks.

Michael