build: Add commit-lint

This commit introduces commitlint, a tool to enforce conventional commit
messages. This is crucial for the automated release process (issue #32)
to work correctly, as it relies on conventional commit messages to
generate the changelog.

The commit includes the following changes:

- Adds `commitlint.config.js` file that defines commitlint's rules for
conventional commits. This config file ensures commits adhere to the
Conventional Commits specification, allowing for automated changelog
generation.
- Adds a `.husky/commit-msg` hook which ensures that commitlint is run
before each commit.
- Adds `@commitlint/cli` and `@commitlint/config-conventional` packages
to `package-lock.json` to enable commitlint functionality.
- Updates `package.json` to add a "commitlint" script, allowing
developers to run commitlint directly.

By enforcing conventional commits, this commit improves the project's
workflow, making releases more reliable and automated. It ensures the
changelog is accurate and consistent, making it easier for developers
and users to understand the project's history and changes.

Author: MikeRatcliffe

.husky/commit-msg

@@ -0,0 +1 @@
+npm run commitlint ${1}

commitlint.config.js

@@ -0,0 +1,65 @@
+/**
+ * This commitlint config file extends the conventional configuration
+ * and adds the following customizations:
+ *
+ * - Ignores commit messages that start with "Merge"
+ * - Allows the following commit types:
+ *   - build
+ *   - chore
+ *   - ci
+ *   - docs
+ *   - feat
+ *   - fix
+ *   - perf
+ *   - refactor
+ *   - revert
+ *   - style
+ *   - test
+ *   - Merge
+ *
+ * Please see the commitlint documentation for more information on how to use
+ * this configuration file:
+ * https://commitlint.js.org/reference/rules.html
+ *
+ */
+const RuleConfigSeverity = {
+  Disabled: 0,
+  Warning: 1,
+  Error: 2,
+};
+
+module.exports = {
+  ignores: [(message) => message.startsWith("Merge")],
+  rules: {
+    "type-enum": [
+      2,
+      "always",
+      [
+        "build",
+        "chore",
+        "ci",
+        "docs",
+        "feat",
+        "fix",
+        "perf",
+        "refactor",
+        "revert",
+        "style",
+        "test",
+      ],
+    ],
+    "body-case": [RuleConfigSeverity.Disabled, "always"],
+    "body-leading-blank": [RuleConfigSeverity.Warning, "always"],
+    "body-max-line-length": [RuleConfigSeverity.Disabled, "always"],
+    "footer-leading-blank": [RuleConfigSeverity.Warning, "always"],
+    "footer-max-line-length": [RuleConfigSeverity.Disabled, "always"],
+    "header-max-length": [RuleConfigSeverity.Disabled, "always"],
+    "header-trim": [RuleConfigSeverity.Error, "always"],
+    "scope-case": [RuleConfigSeverity.Error, "always", "lower-case"],
+    "subject-case": [RuleConfigSeverity.Disabled, "always"],
+    "subject-empty": [RuleConfigSeverity.Error, "never"],
+    "subject-full-stop": [RuleConfigSeverity.Error, "never", "."],
+    "type-case": [RuleConfigSeverity.Error, "always", "lower-case"],
+    "type-empty": [RuleConfigSeverity.Error, "never"],
+  },
+};