Add GH action for routine version updates

[crandmck]

It would be awesome if we could automate docs for routine minor releases. I'm imagining a GH action that would create a PR similar to #1492 for any new release.

At a minimum, each release requires:

• Updating the release change log https://github.com/expressjs/expressjs.com/blob/gh-pages/en/changelog/4x.md with changes for the releases shown in https://github.com/expressjs/express/releases
• Updating the version number in https://github.com/expressjs/expressjs.com/blob/gh-pages/_data/express.yml (used in a couple of places in the docs) with the version number of the release.

Of course, larger releases might require further changes, but I believe this is sufficient for minor versions.