package/containerd: bump version to v1.6.21

https://github.com/containerd/containerd/releases/tag/v1.6.21

Signed-off-by: Christian Stewart <christian@aperture.us>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/containerd/containerd.hash

@@ -1,3 +1,3 @@
 # Computed locally
-sha256  819086ccdca44cfc5f108e226c7a9294d8fad3eb32031a621623da80dedbfb11  containerd-1.6.20.tar.gz
+sha256  9452e95455d03a00d78ae0587595d0c18555bae7912068269efa25a724efe713  containerd-1.6.21.tar.gz
 sha256  4bbe3b885e8cd1907ab4cf9a41e862e74e24b5422297a4f2fe524e6a30ada2b4  LICENSE

package/containerd/containerd.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-CONTAINERD_VERSION = 1.6.20
+CONTAINERD_VERSION = 1.6.21
 CONTAINERD_SITE = $(call github,containerd,containerd,v$(CONTAINERD_VERSION))
 CONTAINERD_LICENSE = Apache-2.0
 CONTAINERD_LICENSE_FILES = LICENSE