Release 0.12.0-alpha.4

[rerun-bot]

Next steps

• Test the release
• If this is an 'alpha' release, you can just merge the pull request.

Web build:

• https://app.rerun.io/version/0.12.0-alpha.4/index.html

Python packages:

• pip install rerun-sdk==0.12.0a4

• Tests

  • Windows
  • Linux (Tested by @jleibs but uncovered several issues during testing -- check does not indicate ready for release)
    • Toggling visibillity on a container doesn't show container contents as hidden in ui #4684
    • Editing columns on a grid container has no effect #4685
    • Bad heuristics for objectron #4689
  • MacOS

[rerun-bot]

Version 0.12.0-alpha.4 published successfully.

artifact	install
web app
wheels	pip install rerun-sdk==0.12.0-alpha.4
crates	cargo install rerun-cli@0.12.0-alpha.4
npm	npm install @rerun-io/web-viewer@0.12.0-alpha.4
docs
py docs
rs docs
cpp_sdk zip