ci: add Dubboctl UI update workflow

[yin1999]

What is the purpose of the change

Fixes: #97.

This PR introduce the "Dubboctl UI Update" workflow which will automatically create a new PR for updating the build asset under the app/dubbo-ui folder.

The workflow's behavior statement:

• Only create the update PR when the build is different than before.
• When a PR changes the related content, this workflow will be triggered to run build test which ensures that the PR changes do not break the build process.
• If the previous update PR is not merged, and the workflow is triggered by the push to the main branch, this workflow will not create a new PR but update the existing PR (whose branch is 'github-actions/dubboctl-ui-update')

How to verify this change

I've tested this workflow in my fork.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ea38a28) 48.52% compared to head (1d1b93f) 48.50%.

❗ Current head 1d1b93f differs from pull request most recent head 1956754. Consider uploading reports for the commit 1956754 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #110      +/-   ##
==========================================
- Coverage   48.52%   48.50%   -0.03%     
==========================================
  Files         148      148              
  Lines        9568     9568              
  Branches       41       41              
==========================================
- Hits         4643     4641       -2     
- Misses       4397     4399       +2     
  Partials      528      528              

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[yin1999]

A workround to fix the bug caused by the resolver.

[chickenlj]

Please configure https://github.com/apache/dubbo-kubernetes/blob/master/.licenserc.yaml to skip license check of the following file:

ERROR the following files don't have a valid license header: 
ui-vue3/.nvmrc 
ERROR one or more files does not have a valid license header 
Error: Process completed with exit code 1.
``