[skip ci] Add auto-changelog stamping, update contributing.md

Author: theogravity

.changelog.js

@@ -12,7 +12,11 @@ module.exports = {
     return 'CHANGELOG.md'
   },
   // ==== Options specific to prepare ====
-  newUnreleasedText: '### UNRELEASED\n\n',
+  newUnreleasedText: `# UNRELEASED
+
+## {{subject}}
+
+{{body}}`,
   unreleasedTag: () => {
     return 'UNRELEASED'
   },

CONTRIBUTING.md

@@ -1,19 +1,29 @@
 # Contributing
 
-- Do *not* version bump package.json unless directed to.
-- Make sure you have appropriate unit tests that cover your feature.
-- Make sure coverage % is maintained.
-- Make sure the `CHANGELOG.md` file is updated.
+- Make sure you have appropriate unit tests that cover your feature
+- Make sure coverage % is maintained
 
-Before you open your PR, run:
+# Changelog
 
-`npm run changelog:prepare`
+If a git commit message looks like this:
 
-and edit `CHANGELOG.md` 
+```text
+This is my commit subject
 
-Place information about what your changes are under section
-marked `# UNRELEASED`.
+This is my commit body
+```
+
+Then the changelog will be stamped in the following fashion on merge:
+
+```text
+# <version> - <date>
+
+## <git subject>
+
+<git body>
+```
 
 # Merging
 
-Once merged, the CI will auto-publish and version bump to npm.
+Once merged, the CI will auto-publish to npm and the changelog will be updated
+with the subject of your commit.

package-lock.json

@@ -19,11 +19,12 @@
     "toc": "toc-md README.md README.md",
     "add-readme": "git add README.md",
     "lint-staged": "lint-staged",
-    "prepare-publish": "npm run changelog:verify && version-bump && npm run changelog:release",
+    "prepare-publish": "npm run changelog:prepare && version-bump && npm run changelog:release && npm run changelog:stamp",
     "version-bump": "version-bump",
     "changelog:help": "changelog-version",
     "changelog:verify": "changelog-version verify",
     "changelog:prepare": "changelog-version prepare",
+    "changelog:stamp": "git-commit-stamper parse CHANGELOG.md",
     "changelog:release": "changelog-version release",
     "lint": "prettier-standard src/**/*.ts && standardx src/**/*.ts",
     "ts-node-dev": "ts-node-dev"
@@ -73,6 +74,7 @@
     "@typescript-eslint/eslint-plugin": "^2.24.0",
     "@typescript-eslint/parser": "^2.24.0",
     "eslint": "6.8.0",
+    "git-commit-stamper": "^1.0.5",
     "jest": "25.1.0",
     "jest-cli": "25.1.0",
     "jest-junit-reporter": "1.1.0",