smoke: use v2.1.6 instead of v2.1.4

[jiangliu]

Update smoke tests to use the latest v2.1.6 instead of v2.1.4.

Relevant Issue (if applicable)

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Details

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Types of changes

What types of changes does your PullRequest introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

Go over all the following points, and put an x in all the boxes that apply.

• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[anolis-bot]

@jiangliu , a new test job has been submitted. Please wait in patience. The test job url: https://tone.openanolis.cn/ws/nrh4nnio/test_result/75349

[anolis-bot]

@jiangliu , The CI test is completed, please check result:

Test Case		Test Result
nydus_ci		❌ FAIL

Sorry, your test job failed. Please get the details in the link.

[codecov]

Codecov Report

Merging #1302 (d471db8) into master (8517120) will increase coverage by 0.26%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1302      +/-   ##
==========================================
+ Coverage   45.65%   45.91%   +0.26%     
==========================================
  Files         123      123              
  Lines       37028    37028              
  Branches    37028    37028              
==========================================
+ Hits        16904    17001      +97     
+ Misses      19235    19133     -102     
- Partials      889      894       +5     

see 6 files with indirect coverage changes