Update Storybook and other monorepo packages in a single PR

[fregante]

Storybook and react-router often cause trouble when their packages are updated separately:

• https://github.com/pixiebrix/pixiebrix-extension/pull/4430
• https://github.com/pixiebrix/pixiebrix-app/pull/2381#commits-pushed-b6fa533
• https://github.com/pixiebrix/pixiebrix-app/pull/1782

There's a feature request for native support for this, but no fix in sight:

• https://github.com/dependabot/dependabot-core/issues/1190
• https://github.com/dependabot/dependabot-core/issues/1296

Possible solutions:

• https://github.com/hrvey/combine-prs-workflow
• custom solution:
  1. Block all secondary storybook/* dependencies
  2. Allow a single storybook/core dependabot PR
  3. Add workflow to run npx sb@latest upgrade and commit on it

Current situation (which is also ok):

1. Understand that these PRs may fail for this reason
2. Manually push grouped updates when that happens