Prepare for v0.3.0. (#20)

diff --git a/README.md b/README.md
index f97f6d7..2ee195a 100644
--- a/README.md
+++ b/README.md
@@ -122,7 +122,7 @@
 
 ```yaml
 - repo: https://github.com/google/keep-sorted
-  rev: v0.2.0
+  rev: v0.3.0
   hooks:
     - id: keep-sorted
 ```