Fixes#6563 by extending the allowed values of the `state` parameter to
include `latest`. To do this, the `update_flat()` function is introduced
which borrows the majority of its implementation from both the existing
`install_flat()` and `remove_flat()` functions. The documentation and
examples have been expanded describing what to expect when using
`state=latest`.
* Similar version restrictions than flatpak_remote tests.
* ...
* Try to work around missing dependencies.
* Revert "Try to work around missing dependencies."
This reverts commit 66a4e38566.
* Add changelog.
* App8 -> App2; make sure that there are two apps App1 and App2.
* Fix forgotten variabe.
* Remove test notices.
* Seems like flatpak no longer supports file:// URLs.
The tests would need to be rewritten to offer the URL via http:// instead.
* Try local HTTP server for URL tests.
* ...
* Lint, add status check.
* Add boilerplate.
* Add 'ps aux'.
* Surrender to -f.
* Work around apparent flatpak bug.
* Fix YAML.
* Improve condition.
* Make sure test reruns behave better.
