Bump rules version in the readme. (#45)

diff --git a/README.md b/README.md
index c5edff3..735467c 100644
--- a/README.md
+++ b/README.md
@@ -34,8 +34,8 @@
 this:
 
 ```build
-kotlin_release_version="1.2.21"
-rules_kotlin_version = "86bf70875361bcdce7fa8977cb60dcd389cb73a3"
+kotlin_release_version="1.2.30"
+rules_kotlin_version = "67f4a6050584730ebae7f8a40435a209f8e0b48e"
 
 http_archive(
     name = "io_bazel_rules_kotlin",