v0.7.0

[tongyiming]

Checklist

• Create the new release branch with minor version, i.e. release-0.21 for v0.21.0.
  • You can use the existing branch for patch releases.
• Tag release by running Tag action in Github UI against release branch, i.e. release-X branch.
  • Use v-prefixed version, like v0.21.0, for both description and tag.
• Run CI action against release branch.
• Tag the next pre-release by running Tag action in Github UI against master branch, if it's not a patch release.
  • The tag should be v0.22.0-rc.0 if you're releasing v0.21.x.
• Validate that you can install the published version, basic sanity check.
• Run Promote action to promote it in alpha channel if it's pre-1.0.
• Use Github UI to generate release notes.
  • Make sure to scan all PRs marked with breaking-change and add instructions for users to handle them.
• Create the next release issue with a title that has its date, 4 weeks after the current release day.
• Announce in Slack, Twitter etc.