This pull:
- removes zenhub option from package.json
- installs and implement `merge-config` package. This allows for usage of environment variables and command line variables along with `package.json` configuration for the changelog generation.
- implements new variable: `devNoteLabel` for indicating what label indicates the pull has (or requires) a devnote. Pull Requests with this label will have `[DN]` appended to the changelog entry.
- adds new variable: `changelogSrcType` for indicating what source to use for generating changelogs (can be `MILESTONE` or `ZENHUB_RELEASE`). Implemented detection of this in code, defaults to `MILESTONE`.
- Modify initial setup text so if user already has api key(s) setup, then we don't give instructions again. Also improve the output when keys aren't set to make it clear what needs done.
- Make the environment variable for Zenhub Api token consistent with Github token (`ZH_API_TOKEN` instead of `ZH_API_KEY`).
- Update package.json with changelog script variation for running it with zenhub release as the source.
- Update `RELEASE.md` docs to clarify changelog script options
- Add a `README.md` doc for the changelog script.
The changelog script now has the following:
- constructed more modularly for easier maintenance.
- removed coupling to blocks repository so it can be used in more contexts (potentially publishing as it's own package).
- switched to use github v4 api (graphql) to reduce number of requests (reducing the likelihood of hitting api limits)
- added support for zenhub releases instead of github milestones for what pulls to derive changelog from.
Darren Ethier