nydus: bump nydus versions in Dockerfile and doc

Nydus has released more stable versions

Signed-off-by: Changwei Ge <[email protected]>

Author: Changwei Ge

Dockerfile

@@ -10,7 +10,7 @@ ARG CNI_VERSION=v1.2.0
 ARG STARGZ_SNAPSHOTTER_VERSION=v0.14.3
 ARG NERDCTL_VERSION=v1.3.0
 ARG DNSNAME_VERSION=v1.3.1
-ARG NYDUS_VERSION=v2.1.0
+ARG NYDUS_VERSION=v2.1.6
 ARG MINIO_VERSION=RELEASE.2022-05-03T20-36-08Z
 ARG MINIO_MC_VERSION=RELEASE.2022-05-04T06-07-55Z
 ARG AZURITE_VERSION=3.18.0

docs/nydus.md

@@ -16,7 +16,7 @@ go build -tags=nydus -o ./bin/buildkitd ./cmd/buildkitd
 
 ### Building Nydus with BuildKit
 
-Download `nydus-image` binary from [nydus release page](https://github.com/dragonflyoss/image-service/releases) (require v2.1.0 or higher), then put the `nydus-image` binary path into $PATH or specifying it on `NYDUS_BUILDER` environment variable for buildkitd:
+Download `nydus-image` binary from [nydus release page](https://github.com/dragonflyoss/image-service/releases) (require v2.1.6 or higher), then put the `nydus-image` binary path into $PATH or specifying it on `NYDUS_BUILDER` environment variable for buildkitd:
 
 ```
 env NYDUS_BUILDER=/path/to/nydus-image buildkitd ...