docs(semantic-release): implement an automated changelog

plus docs on contributing, testing

release-rules.js

@@ -0,0 +1,18 @@
+// No release is triggered for the types commented out below.
+// Commits using these types will be incorporated into the next release.
+//
+// NOTE: Any changes here must be reflected in `CONTRIBUTING.md`.
+module.exports = [
+  {breaking: true, release: 'major'},
+  // {type: 'build', release: 'patch'},
+  // {type: 'chore', release: 'patch'},
+  // {type: 'ci', release: 'patch'},
+  {type: 'docs', release: 'patch'},
+  {type: 'feat', release: 'minor'},
+  {type: 'fix', release: 'patch'},
+  {type: 'perf', release: 'patch'},
+  {type: 'refactor', release: 'patch'},
+  {type: 'revert', release: 'patch'},
+  {type: 'style', release: 'patch'},
+  {type: 'test', release: 'patch'},
+];