chore: add standard-version and release script

This commit adds the `standard-version` module for managing releases.
When running `npm run release` the following steps are taken.

1. Retreive the current version of your repository by looking at package.json.
2. Bump the version in package.json based on the commits.
3. Prepends to the CHANGELOG based on the commits (uses conventional-changelog under the hood).
4. Create a new commit including the package.json and updated CHANGELOG.
5. Create a new tag with the new version number.

This works best if all commits follow the Conventional Commits specification.
https://www.conventionalcommits.org/en/v1.0.0/

Fixes: #56

Signed-off-by: Lance Ball <[email protected]>

Author: lance

CHANGELOG.md

@@ -14,6 +14,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 - Removed support for Node.js 6, 7 and 8 - all of which are EOL at this point. Travis CI modified to test on Node.js 10 and 12.
 
+### Added
+
+- Added support for standard-version and conventional-changelog
+
 ## [1.0.0]
 
 ### Added