Support custom caddy builds in the update script

[dhenry437]

Support for custom caddy builds as per https://caddyserver.com/docs/build#package-support-files-for-custom-builds-for-debianubunturaspbian

I wanted to make you aware that I am meticulous when it comes to merging code into the main branch, so please don't take it personally if I reject your request.

Description

Added caddy upgrade after apt upgrade to upgrade caddy and pull in any custom plugins.

Here it details how to use dpkg-divert to replace the caddy binary with a custom one.

caddy upgrade would then pull in any plugins that are in use.

More details in this support thread

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

[tteck]

If a user is running custom caddy binaries, they should already know this, correct?

[dhenry437]

Exactly, but this would just remove the need to manually run caddy upgrade after an upgrade, tested running caddy upgrade on a vanilla install and it doesn't seem to have any adverse effects.

[tteck]

Since the script utilizes standard Caddy, I don't think adding an unnecessary extra command is needed. But thanks anyway.