run.sh: provide a flag to indicate major version

[damithc]

Context: see https://reposense.org/ug/runSh.html

Suggested: provide a way to specify that the latest release of a specific major version should be used.
For example --version 3.* will use the latest version that starts with 3.

Justification: This way, the user can take advantage of latest bug fixes while avoiding breaking changes (assuming breaking changes will only be introduced in new major versions)