v1.4.0

Add support for a HAPPO_BEFORE_SHA_TAG_MATCHER environment variable. This is intended to be used when you need to resolve the base/before commit sha from a tag. happo-e2e will look at git tags in your repository matching the environment variable value and pick the most recent one (excluding the current commit).

For instance, if you want to compare against the latest release, and your releases are tagged with something like release-2022-10-12, you can set HAPPO_BEFORE_SHA_TAG_MATCHER=release-* and a comparison between the current commit and the most recent release will be made.