Document #SkipVersionBump mechanism and versioning workflow in README

[lukasmatta]

Currently, the CI/CD pipeline automatically bumps the minor version on every push to master that touches projects/cps-ui-kit/**. However, this behavior is not documented anywhere, making it unclear to contributors how versioning works or how to control it.

There is also a mechanism to skip the automatic version bump by including #SkipVersionBump in the commit message, which is useful when a contributor wants to publish a major or patch version instead. In that case, the contributor should:

Manually update the version in package.json to the desired version.
Include #SkipVersionBump in the commit message so the pipeline doesn't overwrite the manual version change with an automatic minor bump.

This workflow is defined in the GitHub Actions workflow cps-ui-kit-publish.yml:13 but is not documented, making it easy for contributors to miss.