Migrate to containerd v1.7.0 and update dependencies

* Updates containerd to v1.7.0 and new binary for 32-bit
Arm OSes.
* Updates Go dependencies - openfaas and external

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/moby/sys/sequential/doc.go

@@ -0,0 +1,15 @@
+// Package sequential provides a set of functions for managing sequential
+// files on Windows.
+//
+// The origin of these functions are the golang OS and windows packages,
+// slightly modified to only cope with files, not directories due to the
+// specific use case.
+//
+// The alteration is to allow a file on Windows to be opened with
+// FILE_FLAG_SEQUENTIAL_SCAN (particular for docker load), to avoid eating
+// the standby list, particularly when accessing large files such as layer.tar.
+//
+// For non-Windows platforms, the package provides wrappers for the equivalents
+// in the os packages. They are passthrough on Unix platforms, and only relevant
+// on Windows.
+package sequential