community/glab: set proper build version

glab by default uses `git describe` output to determine the glab version
during build that is reported by `glab version`.

As the package is built in the aports git repository, it will use the
aports version, rather than the glab version.

Explicitly provide `GLAB_VERSION` to the make command to fix this.
7 jobs for !18252 with glab-fix-version in 4 minutes and 2 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Lint
passed #321701
docker-alpine x86_64
lint

00:00:20

 
  Build
passed #321706
docker-alpine ci-build aarch64
build-aarch64

00:01:02

passed #321707
docker-alpine ci-build armv7
build-armv7

00:01:37

passed #321705
docker-alpine ci-build ppc64le
build-ppc64le

00:03:42

passed #321704
docker-alpine ci-build s390x
build-s390x

00:01:21

passed #321703
docker-alpine ci-build x86
build-x86

00:00:45

passed #321702
docker-alpine ci-build x86_64
build-x86_64

00:01:32