workflow for release

if a tag vXX.XX.XX is puhed , the following will auto trigger:

1 build the images with the pushed tag, push to ghcr registry

2 generate the changelog by historical PR with "pr/release/*"

submit the changelog file to branch 'github_pages', with PR label "pr/release/robot_update_githubpage".

3 build the chart package with the pushed tag, and submit a PR to branch 'github_pages'

it commits the new chart package to '/charts' and update /index.yaml on the branch 'github_pages'

4 submit '/docs' of branch 'main' to '/docs' of branch 'github_pages'

5 create a Github Realse attached with the chart and changelog

finnally, by hand, need approve the chart PR with label "pr/release/robot_update_githubpage" , and changelog PR with label "pr/release/robot_update_githubpage"