Record the git ID used for the build in the log

[Sebastien Bacher]

Currently the gnome sdk build a libsecret part from git, I'm trying to figure out which revision was current at the time of the last snap build but that information doesn't seem to be available?

The build log has those information

Pulling libsecret
+ snapcraftctl pull
Cloning into '/build/gnome-3-38-2004-sdk/parts/libsecret/src'...
[07/Jan/2022:17:00:37 +0000] "CONNECT gitlab.gnome.org:443 HTTP/1.1" 200 327888 "-" "git/2.25.1"
'libgnome-games-support' has dependencies that need to be staged: libsecret
Skipping pull libsecret (already ran)
Building libsecret
+ snapcraftctl build

The snap/manifest.yaml has the information but it would be nice if the build log had it also, especially in case where the build is failing and where we don't have a manifest available

One way would be to call 'git reflog' or an equivalent after the cloning