Install git, add to the README

We use git in the makefile to create the container revision label.
This did not have any affect outside the local containers, since the
official ones use the CI_COMMIT_TAG variable from the CI.

Fixes: 5ec09f5 ("gitlab-ci: install devtools without its dependencies")
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

.gitlab-ci.yml

@@ -62,7 +62,7 @@ get_version:
     matrix:
       - GROUP: [base, base-devel]
   before_script:
-    - pacman -Syu --noconfirm make fakechroot fakeroot
+    - pacman -Syu --noconfirm git make fakechroot fakeroot
     - pacman -Sdd --noconfirm devtools
   script:
     - make $PWD/output/Dockerfile.$GROUP

README.md

@@ -54,7 +54,8 @@ image for Arch Linux.
 Install the following Arch Linux packages:
 
 * make
-* devtools
+* devtools (for the pacman.conf files)
+* git (to fetch the commit/revision number)
 * podman
 * fakechroot
 * fakeroot