Subject: Minetest can't retrieve packages for additional content due to SSL certificate either invalid or not available

From: pkill9 <[email-masked]>
Date: Sun, 29 Mar 2020 17:17:25 +0100

To reproduce, run Minetest, then go to Content > Browse Online Content,
and it says 'No packages could be retrieved', and in the terminal it
returns `ERROR[Main]:
https://content.minetest.net/api/packages/?type=mod&type=game&type=txp&protocol_version=38&hide=nonfree&hide=desktop_default
not found (SSL peer certificate or SSH remote key was not OK) (response
code 0)`