Update srcimporter.go to golang/go@5f0a9ba

Also move to third_party/ as it's copied code.

third_party/go-srcimporter/BUILD

@@ -0,0 +1,24 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+licenses(["notice"])
+
+go_library(
+    name = "go_default_library",
+    srcs = ["srcimporter.go"],
+    importpath = "k8s.io/kubernetes/third_party/go-srcimporter",
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)