Update github.com/opencontainers/runtime-tools to v0.6.0

Also add new dependencies on github.com/xeipuuv/gojson* (brought up by
new runtime-tools) and adapt the containerd/cri code to replace the APIs
that were removed by runtime-tools.

In particular, add new helpers to handle the capabilities, since
runtime-tools now split them into separate sets of functions for each
capability set.

Replace g.Spec() with g.Config since g.Spec() has been deprecated in the
runtime-tools API.

Signed-off-by: Filipe Brandenburger <filbranden@google.com>

vendor/github.com/opencontainers/runtime-tools/specerror/config-windows.go

@@ -0,0 +1,32 @@
+package specerror
+
+import (
+	"fmt"
+
+	rfc2119 "github.com/opencontainers/runtime-tools/error"
+)
+
+// define error codes
+const (
+	// WindowsLayerFoldersRequired represents "`layerFolders` MUST contain at least one entry."
+	WindowsLayerFoldersRequired Code = 0xd001 + iota
+	// WindowsHyperVPresent represents "If present, the container MUST be run with Hyper-V isolation."
+	WindowsHyperVPresent
+	// WindowsHyperVOmit represents "If omitted, the container MUST be run as a Windows Server container."
+	WindowsHyperVOmit
+)
+
+var (
+	layerfoldersRef = func(version string) (reference string, err error) {
+		return fmt.Sprintf(referenceTemplate, version, "config-windows.md#layerfolders"), nil
+	}
+	hypervRef = func(version string) (reference string, err error) {
+		return fmt.Sprintf(referenceTemplate, version, "config-windows.md#hyperv"), nil
+	}
+)
+
+func init() {
+	register(WindowsLayerFoldersRequired, rfc2119.Must, layerfoldersRef)
+	register(WindowsHyperVPresent, rfc2119.Must, hypervRef)
+	register(WindowsHyperVOmit, rfc2119.Must, hypervRef)
+}