curl -O https://letsencrypt.org/certs/isrgrootx1.pem
curl -O https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.pem
openssl x509 -in isrgrootx1.pem -inform PEM -out isrgrootx1.crt
openssl x509 -in lets-encrypt-x3-cross-signed.pem -inform PEM -out lets-encrypt-x3-cross-signed.crt
sudo cp *.crt /usr/local/share/ca-certificates/
sudo update-ca-certificates --verbose
I already trust 148, your new list has 150
Certificate added: C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
1 new root certificates were added to your trust store.
...
sudo systemctl restart docker