fix(release): missed a public API symbol that requires re-export (#1094)

Broken by #1083

Author: alexeagle

lib/tar.bzl

@@ -1,10 +1,13 @@
 """Re-export of https://registry.bazel.build/modules/tar.bzl to avoid breaking change.
+https://github.com/bazel-contrib/bazel-lib/pull/1083 moved these symbols to tar.bzl
 TODO(3.0): delete
 """
 
 load("@tar.bzl//tar:mtree.bzl", _mtree_mutate = "mtree_mutate", _mtree_spec = "mtree_spec")
-load("@tar.bzl//tar:tar.bzl", _tar = "tar")
+load("@tar.bzl//tar:tar.bzl", _tar = "tar", _tar_lib = "tar_lib", _tar_rule = "tar_rule")
 
 mtree_mutate = _mtree_mutate
 mtree_spec = _mtree_spec
 tar = _tar
+tar_lib = _tar_lib
+tar_rule = _tar_rule