Automate releases

[foolip]

Let's automate releases more, so that we can quickly release and publish both a GitHub release with data.json and the npm package.

• Automate publishing to NPM when a tag is pushed (Publish web-features to NPM on v1.2.3 style tag #1479)
• Set up something like https://github.com/googleapis/release-please to prepare releases in a pull request. Or something that maintains a draft GitHub release.

[foolip]

@jcscottiii suggested that we can copy from https://github.com/mdn/browser-compat-data/blob/main/.github/workflows/release.yml

There are also some goodies in https://github.com/w3c/webref/blob/main/.github/workflows/release-package.yml to take inspiration from.

[ddbeck]

#11 (comment) outlined some work done or planned for automating releases as well.

[foolip]

@ddbeck and I have discussed this a few times, and concluded it makes sense to work backwards, first automating the publishing to NPM, then the creation of tags and GitHub releases. I'll update the description with a list of checkboxes.

[foolip]

These are the steps I take to make a release manually now:

• Send a PR to update packages/web-features/package.json and ackages/web-features/package-lock.json (I edit the first and then run npm i to update the second.)
• Wait for that PR to be approved
• Merge the PR and immediately go to https://github.com/web-platform-dx/web-features/releases/new
• Fill in the tag name vX.Y.Z manually as both the tag and release title
• For major releases, add a "Breaking Changes" section up top. For minor releases, add a "What's New" section up top.
• Click "Generate release notes"
• Search for "<" and make sure all element names are quoted with backquotes
• Remove all lines from Dependabot
• Locally, update main and run npm run build and npm run build:extended
• Upload data.json, data.extended.json and data.schema.json as release artifacts
• Publish GitHub release

The last step creates the Git tag. So far I have been running npm publish manually but that should now get done automatically.

I also take make sure I don't have a stale checkout or anything built from a previous state of the repo when I publish. Sometimes by running git clean -fdx before I start, and sometimes by just running npm ci in the root and inside packages/web-features.

[foolip]

I've sent #1559 and #1560, and believe that with those two landed, releases are automated enough to not be a blocker for #1240.