Release server TLS Cert
After the Updater not present build last summer, we switched to a Digicert (1-year?) TLS Cert as the root was trusted by the updater code on the device.
Once that expires, we can either renew or go back to Let's Encrypt certs.
Let's Encrypt worked just fine normally, it was only for this special case it didn't work (#110 (closed))
There's a patch to trust all roots on gerrit, https://review.calyxos.org/c/CalyxOS/platform_system_update_engine/+/618 - that we should test and merge soon.