Bump github.com/containerd/containerd

Bumps [github.com/containerd/containerd](https://github.com/containerd/containerd) from 1.6.3-0.20220401172941-5ff8fce1fcc6 to 1.6.18.
- [Release notes](https://github.com/containerd/containerd/releases)
- [Changelog](https://github.com/containerd/containerd/blob/main/RELEASES.md)
- [Commits](https://github.com/containerd/containerd/commits/v1.6.18)

---
updated-dependencies:
- dependency-name: github.com/containerd/containerd
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

go.mod

@@ -10,7 +10,7 @@ require (
 
 require (
 	github.com/agext/levenshtein v1.2.3 // indirect
-	github.com/containerd/containerd v1.6.3-0.20220401172941-5ff8fce1fcc6 // indirect
+	github.com/containerd/containerd v1.6.18 // indirect
 	github.com/containerd/ttrpc v1.1.0 // indirect
 	github.com/containerd/typeurl v1.0.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
@@ -22,8 +22,10 @@ require (
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/klauspost/compress v1.15.1 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/moby/locker v1.0.1 // indirect
 	github.com/moby/sys/signal v0.6.0 // indirect
+	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
@@ -33,9 +35,10 @@ require (
 	golang.org/x/net v0.7.0 // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
 	golang.org/x/sys v0.5.0 // indirect
-	google.golang.org/genproto v0.0.0-20211208223120-3a66f561d7aa // indirect
-	google.golang.org/grpc v1.45.0 // indirect
-	google.golang.org/protobuf v1.27.1 // indirect
+	google.golang.org/genproto v0.0.0-20220502173005-c8bf987b8c21 // indirect
+	google.golang.org/grpc v1.47.0 // indirect
+	google.golang.org/protobuf v1.28.0 // indirect
+	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )