Makes package public by default

When creating a skylark_library A anywhere downstream, if a bzl file in A loads() any of the bzl libraries in this package, then the bzl files in this package will have to be in deps as a skylark_library. The current public filegroup cannot be used as a dependency of skylark_libraries.

lib/BUILD

diff --git a/lib/BUILD b/lib/BUILD
index 4b6fa04..eaab8a6 100644
--- a/lib/BUILD
+++ b/lib/BUILD
@@ -1,6 +1,6 @@
 licenses(["notice"])
 
-package(default_visibility = ["//:__pkg__"])
+package(default_visibility = ["//visibility:public"])
 
 load("//:skylark_library.bzl", "skylark_library")