petitboot-1.2.0 released

[Samuel Mendoza-Jonas]

While I started tagging releases of Petitboot in March I've neglected to
discuss them much on the list, but now seems as good a time as any to
start :)

v1.0.0 was tagged on March 21st largely since we needed to start
somewhere, and since then there have been four more releases.

Some notable changes since v1.0.0:
- discover/devmapper: Read device size from sysfs
	This allows the use of device-mapper snapshots on additional
	devices such as software RAID arrays and NVMe storage.
- discover: Perform pre-boot steps when timeout expires
	Fixes an issue where IPMI overrides would not be properly
	cleared after an automatic boot.
- ui/ncurses: Start UI before connected to server
	This is particularly useful for Petitboot instances where the UI
	can come up well before the pb-discover process, with kernels
	compiled with modules being a notable example.
- discover/platform-powerpc: Return bootdev error correctly
	Fixes an issue where an IPMI override could be erroneously
	applied.

Changes since v1.1.1:
- Asynchronous PXE requests
	The PXE parser has been updated to request config files
	asynchronously, allowing the pb-discover process to continue
	while waiting for a response. This fixes an annoying issue where
	issues with a DHCP server's configuration could cause TFTP
	requests to timeout, making pb-discover appear to hang for long
	periods of time.
- Set linux,stdout-path before boot
	Petitboot now updates the linux,stdout-path device-tree property
	before boot depending on a saved value (on autoboot) or the
	current UI (on manual boot). This informs the target kernel
	which console to use as the primary console during boot, giving
	a more consistent experience across kexec.