chore: add workflow for versioning/publishing blockly

[maribethb]

The basics

• I validated my changes

The details

Resolves

Fixes #9550

Proposed Changes

Adds a workflow for versioning and publishing blockly:

• runs the same ci as happens on a PR: build/test/lint etc
• includes dry-run option which only prints the version number
• automatically determines the version number (using the same underlying package that lerna version uses when it does this for us in samples) based on conventional commits
• publishes to npm (need to set up trusted publishing once this workflow exists)
• creates a github release with automated release notes, tag, and the tarball

Reason for Changes

Improved ease of publishing

Test Coverage

I haven't tested this. Will first test using the dry run option to make the version number works correctly. Otherwise, the steps here match what we do when publishing a manual release.

Documentation

Will update internal documentation on publishing.

Additional Information

Next steps:

• add option to publish a beta version and from other branches
• add a call to the update github pages workflow after a successful publish

[maribethb]

oops forgot to add the dry run commit previously, PTAL