feat: add option strip_prefix

[tpope]

This is #77 rebased with the requested documentation change.

[andreiborza]

Hey @tpope, thanks for the contribution.

We are currently in the process of evaluating what kind of options we want to keep around for this action and which to drop, I will keep this PR around until we have a clearer picture. That being said, could you provide a motivation for this change to help us make the decision easier? Would love to hear a bit about your workflow and what you're currently doing without this option.

[tpope]

I have a Node.js project that follows the common idiom of generated compiled assets into dist/, resulting in "sources" paths like ../src/foo.ts, ../node_modules/foo/index.js, etc. --url-prefix=/something --strip-prefix=.. is the only way I've found to prevent Sentry from including ../ in the final resolved stack trace paths.

The project is using legacy source maps and cannot be easily retooled to use debug IDs, for reasons.

[andreiborza]

Thank you for the swift answer. I'll bring this up with the team and will let you know. Thanks again for the contribution!