Update WORKSPACE for v2.15.1

WORKSPACE

@@ -17,6 +17,32 @@ tf_serving_workspace()
 load("@bazel_skylib//lib:versions.bzl", "versions")
 versions.check("6.4.0")
 
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "bazel_skylib",
+    sha256 = "74d544d96f4a5bb630d465ca8bbcfe231e3594e5aae57e1edbf17a6eb3ca2506",
+    urls = [
+        "https://storage.googleapis.com/mirror.tensorflow.org/github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
+    ],
+)
+
+http_archive(
+    name = "rules_python",
+    sha256 = "84aec9e21cc56fbc7f1335035a71c850d1b9b5cc6ff497306f84cced9a769841",
+    strip_prefix = "rules_python-0.23.1",
+    url = "https://github.com/bazelbuild/rules_python/releases/download/0.23.1/rules_python-0.23.1.tar.gz",
+)
+
+load("@rules_python//python:repositories.bzl", "python_register_toolchains")
+
+python_register_toolchains(
+    name = "python",
+    ignore_root_user_error = True,
+    python_version = "3.9",
+)
+
 # Initialize TensorFlow's external dependencies.
 load("@org_tensorflow//tensorflow:workspace3.bzl", "workspace")
 workspace()