This will allow us to more quickly update a dependency by adding support so that downstream repos can auto-push updates to the main repo when there is a release.
While we will still build for 18.04, we will now stop testing against it. Instead, we will test against 20.04, the next EOL release after 18.04.
Once Ubuntu 18.04 is EOL, any references to it will also be removed.
Note that 18.04 support was already deprecated in Dokku 0.28.0, so this change is just acknowledging that deprecation.
This specifically targets Raspbian Buster, though releases may work on other debian-based operating systems.
Note that this does _not_ port buildpacks - either herokuish or pack - to Raspbian, and it is likely that users will need to use pack for buildpack support (if/when it is supported on ARM) or Dockerfile for image building.
While the latest packages may continue to work on other releases, we will no longer officially support these releases, nor will we distribute packages.
This moves the base image from Xenial to Bionic, which is the latest supported LTS release of Ubuntu. Note that all previous releases of herokuish are no longer supported, and users are encouraged to upgrade where possible.
In the case of upgrades, a 'dokku repo:purge-cache APP' should be called for each app, or built applications may include code linked to non-ABI compatible libraries due to the OS upgrade.
This sort of change is usually performed _only_ during a minor release, but as the window since the release is fairly small, the risk to our users is negligible in comparison to the inability to stay on a maintained herokuish release.
This only completes the command names - not any arguments - and also relies on a completion cache as the response from Dokku for help output can be slow.
Closes#2095
This removes the ability to support http proxy directly, but fixes issues where users may not
be using exactly the same herokuish as we expect.
Closes#2828
[ci skip]
