Update dependency bazel_skylib to v1.4.0

Author: renovate[bot]

WORKSPACE

@@ -8,10 +8,10 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
     name = "bazel_skylib",
-    sha256 = "74d544d96f4a5bb630d465ca8bbcfe231e3594e5aae57e1edbf17a6eb3ca2506",
+    sha256 = "f24ab666394232f834f74d19e2ff142b0af17466ea0c69a3f4c276ee75f6efce",
     urls = [
-        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.4.0/bazel-skylib-1.4.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.4.0/bazel-skylib-1.4.0.tar.gz",
     ],
 )