Update to use go modules (#671)

This includes updates to CI config, vendor files, etc.
I've hard-coded the k8s depedency at 1.13.4 to keep it inline with what
we currently have and to make sure a another run of `go mod tidy`
doesn't accidentally update it to an unexpected version.

Thanks to hectorj2f for carrying this along.

vendor/k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1/BUILD

@@ -0,0 +1,26 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["types.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1",
+    deps = ["//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

vendor/k8s.io/kubernetes/pkg/kubelet/envvars/BUILD

@@ -0,0 +1,43 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "doc.go",
+        "envvars.go",
+    ],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/envvars",
+    deps = [
+        "//pkg/apis/core/v1/helper:go_default_library",
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["envvars_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

vendor/k8s.io/kubernetes/pkg/kubelet/server/remotecommand/BUILD

@@ -0,0 +1,46 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "attach.go",
+        "doc.go",
+        "exec.go",
+        "httpstream.go",
+        "websocket.go",
+    ],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/server/remotecommand",
+    deps = [
+        "//pkg/apis/core:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/httpstream:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/httpstream/spdy:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/remotecommand:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/server/httplog:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/util/wsstream:go_default_library",
+        "//staging/src/k8s.io/client-go/tools/remotecommand:go_default_library",
+        "//vendor/k8s.io/klog:go_default_library",
+        "//vendor/k8s.io/utils/exec:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)