Add husky & commitlint to enforce conventional-commit messages

.husky/.gitignore

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+_

.husky/commit-msg

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+#!/bin/sh
+BRANCH_NAME=$(git branch | grep '*' | sed 's/* //')
+
+if [ $BRANCH_NAME != '(no branch)' ]
+then
+    # don't run hook when rebasing
+    . "$(dirname "$0")/_/husky.sh"
+
+    npx --no-install commitlint --edit
+fi

commitlint.config.js

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+module.exports = {
+    extends: ['@commitlint/config-conventional'],
+    rules: {
+        // don't care about line length
+        // 200 seems generous, also just warn
+        'header-max-length': [1, 'always', 200],
+        'body-max-line-length': [1, 'always', 200],
+        'footer-max-line-length': [1, 'always', 200],
+        // don't care about case
+        'header-case': [0, 'always', 'lower-case'],
+        'subject-case': [0, 'always', 'lower-case'],
+        'body-case': [0, 'always', 'lower-case'],
+        // don't care about trailing full-stop.
+        'subject-full-stop': [0, 'never', '.'],
+        'header-full-stop': [0, 'never', '.'],
+        // valid types + descriptions
+        // feel free to add more types as necessary
+        'type-enum': [2, 'always', [
+            'build', // Changes that affect the build system
+            'ci', // Changes to our CI configuration files and scripts.
+            'docs', // Documentation only changes
+            'feat', // A new feature
+            'fix', // A bug fix
+            'perf', // A code change that improves performance
+            'refactor', // A code change that neither fixes a bug nor adds a feature
+            'style', // Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
+            'test', // Adding missing tests or correcting existing tests
+            'revert', // git revert
+            'deps', // Changes that affect external dependencies e.g. refreshing package-lock, updating deps.
+            'deploy', // for gh-pages
+        ]],
+    }
+}