Update hcsshim and go-winio vendoring

* Update hcsshim to v0.8.14
* Update go-winio to v0.4.16

This brings in some vhd package changes from winio, and the compute storage api bindings for
the shim. This is to facilitate some coming functionality for the windows snapshotter
as well as possibly for future work down the line for the windows differ.

Signed-off-by: Daniel Canter <dcanter@microsoft.com>

vendor/github.com/Microsoft/hcsshim/computestorage/initialize.go

@@ -0,0 +1,38 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"go.opencensus.io/trace"
+)
+
+// InitializeWritableLayer initializes a writable layer for a container.
+//
+// `layerPath` is a path to a directory the layer is mounted. If the
+// path does not end in a `\` the platform will append it automatically.
+//
+// `layerData` is the parent read-only layer data.
+func InitializeWritableLayer(ctx context.Context, layerPath string, layerData LayerData) (err error) {
+	title := "hcsshim.InitializeWritableLayer"
+	ctx, span := trace.StartSpan(ctx, title)
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+	)
+
+	bytes, err := json.Marshal(layerData)
+	if err != nil {
+		return err
+	}
+
+	// Options are not used in the platform as of RS5
+	err = hcsInitializeWritableLayer(layerPath, string(bytes), "")
+	if err != nil {
+		return fmt.Errorf("failed to intitialize container layer: %s", err)
+	}
+	return nil
+}