git-lfs: Add new version (#13356)

PS: The old versions do not work: it's likely that they changed git
history on submodules

var/spack/repos/builtin/packages/git-lfs/package.py

@@ -16,6 +16,7 @@ class GitLfs(MakefilePackage):
     homepage = "https://git-lfs.github.com"
     url      = "https://github.com/git-lfs/git-lfs/archive/v2.6.1.tar.gz"
 
+    version('2.9.0', sha256='f1963ad88747577ffeeb854649aeacaa741c59be74683da4d46b129a72d111b7')
     version('2.8.0', sha256='10b476bb8862ebceddc6f0a55f5fb63e2c1e5bed6554f6e3b207dd0155a196ad')
     version('2.7.2', sha256='e65659f12ec557ae8c778c01ca62d921413221864b68bd93cfa41399028ae67f')
     version('2.7.1', sha256='af60c2370d135ab13724d302a0b1c226ec9fb0ee6d29ecc335e9add4c86497b4')