feat(run): add `input` option

[mkantor]

Rollup Plugin Name: run

This PR contains:

• [ ] bugfix
• [x] feature
• [ ] refactor
• [ ] documentation
• [ ] other

Are tests included?

• [x] yes (bugfixes and features will not be merged without tests)
• [ ] no

Breaking Changes?

• [ ] yes (breaking changes will not be merged unless absolutely necessary)
• [x] no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

Description

This changeset adds an input option to the run plugin. This option allows specifying which entry point to run if you have multiple in your bundle.