Create tox-tarball job

While this job shouldn't be in the check pipeline, add it today so we
can test things.  We are still missing publishers, but that is
expected since we are missing secrets from zuulv3-dev.o.o.

Change-Id: I12a8a0e156cba1c7e5631da5f05478bb0b8ce957
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
diff --git a/.zuul.yaml b/.zuul.yaml
index 847d9e7..98b880d 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -38,6 +38,12 @@
     parent: tox
     run: tox/py27
 
+- job:
+    name: tox-tarball
+    parent: tox
+    run: tox/tarball
+    post-run: tox/tarball-post
+
 - project:
     name: openstack-infra/zuul
     check:
@@ -46,3 +52,4 @@
         - tox-cover
         - tox-linters
         - tox-py27
+        - tox-tarball