feat: get-latest-tag

[erikburt]

This actions tries to fetch the latest tag matching a specific prefix within a github repository.

• It will use semver library to parse the versions contained in the tags, and then attempt to find the "latest" version
• It also produces an output object used to recommend a tag/version depending on a patch/minor/major bump

Notes

This is different from get-latest-github-release which only scrapes github releases, and doesn't have proper filtering or comparison logic for multi-tenant/multi-module repositories.

Testing

Added some unit tests for the parsing, and versioning logic.

Tested locally using scripts/test.sh.

Motivation

This is a piece of the puzzle for DX-2323, which will use apidiff-go and other actions to produce an automated release flow for many repositories.

This action fits into the flow by:

1. For a specific module, getting the most recent release/tag for it
2. apidiff-go will then diff the module from the last release (as opposed to the default of the last commit)
   1. apidiff-go will also produce a list of interface changes as it does, and recommend a version bump (major, minor, or patch), based on simple heuristics
3. Using some basic logic, we will create a "draft" GH release with proper version/tag based on the above

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DX-2323