Use Skylark version of http_archive. (#155)

diff --git a/README.md b/README.md
index a5c3835..7fbc25b 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,8 @@
 this:
 
 ```build
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
 rules_kotlin_version = "67f4a6050584730ebae7f8a40435a209f8e0b48e"
 
 http_archive(