c-go: Update diskv to get atomic fs cache write

vendor/github.com/gregjones/httpcache/diskcache/BUILD

@@ -1,16 +1,9 @@
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])
-
-load(
-    "@io_bazel_rules_go//go:def.bzl",
-    "go_library",
-)
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_library(
     name = "go_default_library",
     srcs = ["diskcache.go"],
-    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
     deps = ["//vendor/github.com/peterbourgon/diskv:go_default_library"],
 )
 
@@ -25,4 +18,5 @@ filegroup(
     name = "all-srcs",
     srcs = [":package-srcs"],
     tags = ["automanaged"],
+    visibility = ["//visibility:public"],
 )