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.

[bjohansebas]

A workflow could be created to detect changes in the history of the Express repository. However, to avoid pulling information about updated dependencies (or irrelevant information), two separate histories could be managed: one for the website and the existing one.

@crandmck I could give it a try if that sounds good to you