Bump rules_pkg to 0.4.0

Author: shs96c

WORKSPACE

@@ -152,8 +152,11 @@ rules_closure_toolchains()
 
 http_archive(
     name = "rules_pkg",
-    sha256 = "aeca78988341a2ee1ba097641056d168320ecc51372ef7ff8e64b139516a4937",
-    url = "https://github.com/bazelbuild/rules_pkg/releases/download/0.2.6-1/rules_pkg-0.2.6.tar.gz",
+    sha256 = "038f1caa773a7e35b3663865ffb003169c6a71dc995e39bf4815792f385d837d",
+    urls = [
+        "https://github.com/bazelbuild/rules_pkg/releases/download/0.4.0/rules_pkg-0.4.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_pkg/releases/download/0.4.0/rules_pkg-0.4.0.tar.gz",
+    ],
 )
 
 http_archive(