To install the fortigate certificate into Linux:
# cp fortigate.cer /etc/pki/ca-trust/source/anchors/fortigate.cer
update-ca-trust extract
In docker
1. Copy certificate into catalog scripts/fortigate.cer
2. Edit Dockerfile, and add this lines:
COPY scripts/fortigate.cer /etc/pki/ca-trust/source/anchors/fortigate.cer
RUN update-ca-trust extract