Use 0.5.0 in README (#562)

Co-authored-by: Jonathon Belotti <jonathon@canva.com>

README.md

diff --git a/README.md b/README.md
index 37b72fe..a35ef7a 100644
--- a/README.md
+++ b/README.md
@@ -42,8 +42,8 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 http_archive(
     name = "rules_python",
-    url = "https://github.com/bazelbuild/rules_python/releases/download/0.4.0/rules_python-0.4.0.tar.gz",
-    sha256 = "954aa89b491be4a083304a2cb838019c8b8c3720a7abb9c4cb81ac7a24230cea",
+    url = "https://github.com/bazelbuild/rules_python/releases/download/0.5.0/rules_python-0.5.0.tar.gz",
+    sha256 = "cd6730ed53a002c56ce4e2f396ba3b3be262fd7cb68339f0377a45e8227fe332",
 )
 ```