Update to 0.7.0 release

Upstream has issued a new upstream release (0.7.0) that I would like to get into Ubuntu.

New Features:
 - Add a version plugin for SteelSeries hardware (Richard Hughes)
 - Add FwupdClient and FwupdResult to libfwupd (Richard Hughes)
 - Generate gtk-doc documentation for libfwupd (Richard Hughes)
 - Return the device flags when getting firmware details (Richard Hughes)
 - Support other checksum kinds (Richard Hughes)

Bugfixes:
 - Add Alienware to the version quirk table (Mario Limonciello)
 - Allow the test suite to run in %check (Richard Hughes)
 - Do not return updates that require AC when on battery (Richard Hughes)
 - Do not use /tmp for downloaded files (Richard Hughes)
 - Test that GPG key import actually was successful (Mario Limonciello)

Many of the bugfixes that were included were documented in the security validation of the MIR for fwupd with the intention to pull them into Ubuntu prior to Ubuntu release. Of particular note, I want to mention that these changes allow the test suite to run at build time (which was previously not possible in sbuild).

Of the new features, FwupdClient and FwupdResult are for new features that are available in gnome-software master. They aren't available in gnome-software 3.20.x (so they won't be used in Ubuntu).

The SteelSeries plugin is for a USB device.

The extra support for getting device flags will assist in debugging why a firmware update isn't running or offered.

The support to check for additional checksums will allow for the online repository to switch to a better hashing algorithm in the future.