feat(action): strip component prefix from tag

[alejandrogr]

Motivation

When creating a component tag, that tag is prefixed with a component-prefix. When we use this tag (for updating a version file or when we return the created tag from the action) may be useful to use it without the component prefix.

closes #6

[alejandrogr]

I don't like how the test are approached in run.test.js. IMHO in those test we must mock all the modules (tags, branches, components...) and move the test in the run.test.js to the corresponding modules.

Anyway, I preferred to leave it as it is and put the test here so as not to get into a bigger refactor. We can add a new issue to make this refactor