build: bump version to v1.6.0-rc1

[simlecode]

Related Issues

close: #4924
close: #4937
close: #4936

Proposed Changes

Additional Info

Checklist

Before you mark the PR ready for review, please make sure that:

• All commits have a clear commit message.
• The PR title is in the form of of <PR type>: <#issue number> <area>: <change being made>
  • example: fix: #1234 mempool: Introduce a cache for valid signatures
  • PR type: fix, feat, INTERFACE BREAKING CHANGE, CONSENSUS BREAKING, build, chore, ci, docs, misc, perf, refactor, revert, style, test
  • area: venus, venus-messager, venus-miner, venus-gateway, venus-auth, venus-market, venus-sealer, venus-wallet, venus-cluster, api, chain, state, vm, data transfer, mempool, message, block production, multisig, networking, paychan, proving, sealing, wallet
• This PR has tests for new functionality or change in behaviour
• If new user-facing features are introduced, clear usage guidelines and / or documentation updates should be included in venus docs or Discussion Tutorials.
• CI is green

[codecov-commenter]

Codecov Report

Merging #4929 (a8b6579) into master (b391a09) will decrease coverage by 0%.
The diff coverage is 16%.

@@           Coverage Diff            @@
##           master   #4929     +/-   ##
========================================
- Coverage      25%     24%     -1%     
========================================
  Files         576     594     +18     
  Lines       62066   64693   +2627     
========================================
+ Hits        15776   16108    +332     
- Misses      44141   46446   +2305     
+ Partials     2149    2139     -10     

[diwufeiwen]

LGTM