Add all-erratum-content to publish exclusions

While investigating another issue I stumbled across this logic. I
imagine it'd be the same case for the new all-erratum-content repos

pubtools/_pulp/tasks/push/items/erratum.py

@@ -86,7 +86,8 @@ def publish_pulp_repos(self):
             #
             # Also note that there's an entire family of these repos, hence the
             # startswith rather than plain equality check.
-            if not repo_id.startswith("all-rpm-content"):
+            if not (repo_id.startswith("all-rpm-content")
+                    or repo_id.startswith("all-erratum-content")):
                 out.add(repo_id)
 
         return sorted(out)

tests/push/test_pulperratumpushitem.py

@@ -23,6 +23,7 @@ def test_erratum_publishes_all_repos():
             repository_memberships=[
                 "all-rpm-content",
                 "all-rpm-content-ff",
+                "all-erratum-content-2019",
                 "existing1",
                 "existing2",
             ],