* Add script to bump major version in README
On lines 29-32, we could alternatively use `replaceAll`, I opted not to
as it is not yet(?) part of an LTS release of NodeJS.
* Bump CDN version in README automatically for new releases
* Rename "bump-cdn-version.js" to "update-cdn-urls.js"
* Update names of file-level constants in update-cdn-urls.js
* Rename workflow setp for updating CDN URLs
* Rename packageJsonFile constant in update-cdn-urls
* Remove semver dependency
* Generalize update-cdn-urls script
