checkout seems to be failing for ubuntu 20 recently:
```
Deleting the contents of '/__w/wezterm/wezterm'
Initializing the repository
/usr/bin/git init /__w/wezterm/wezterm
Initialized empty Git repository in /__w/wezterm/wezterm/.git/
/usr/bin/git remote add origin https://github.com/wez/wezterm
Error: fatal: unsafe repository ('/__w/wezterm/wezterm' is owned by someone else)
To add an exception for this directory, call:
git config --global --add safe.directory /__w/wezterm/wezterm
Error: The process '/usr/bin/git' failed with exit code 128
```
Try reverting this as a workaround.
`gh` is pre-installed in native runners only; when we build in a
container, we need to install it for ourselves.
This commit drops support for building on centos7 as it is a PITA
to get this working there.
This commit reduces the cron schedule for nightly builds down from
hourly and to actually nightly (at ~3am).
The push-to-master flow now triggers effectively the same thing at push
time, so if anything, this will reduce the latency of the continuous
package build and deploy.
The push-to-master flow will now skip builds if it changes only the
docs.
The mac builds started to fail with a crate resolution issue that I
can't reproduce locally shortly after I updated the cache action. Let's
tweak the cache key to see if that clears things up.
tweak some container names
fixup container names and regenerate the config
Ensure that curl is installed
the rust toolchain stuff wants curl
run apt update before apt install
centralize updating apt, and install sudo
revise get-deps script for slimmer debian images
more container related tweaks
get-deps: Don't require lsb-release on debianish systems
more get-deps improvements
Explicitly ask GH actions to recursively checkout the repo
Explicitly install git
fetch tags and tweak git build for debian systems
moar adjustments
remove deb8 (its wayland is too old), fixup debian publish
Ensure git build deps are installed always, tidy up sudo usage
