Add configuration for release-it

This configuration supplies publishing to npm along with making a
release on GitHub with additional assets to be uploaded (in particular
minified versions for both the module and nonmodule variants).

.release-it.json

@@ -1,5 +1,22 @@
 {
+  "git": {
+    "commitMessage": "Craft v${version} release",
+    "requireCleanWorkingDir": false,
+    "tagAnnotation": "Release v${version}",
+    "tagName": "v${version}"
+  },
   "github": {
-    "release": true
+    "assets": [
+      "dist/*.mjs",
+      "dist/*.js"
+    ],
+    "draft": true,
+    "release": true,
+    "releaseName": "v${version}"
+  },
+  "hooks": {
+    "after:bump": "npm run dist",
+    "after:release": "echo Successfully released ${name} v${version} to ${repo.repository}.",
+    "before:init": "npm test"
   }
-}
+}

package.json

@@ -20,6 +20,7 @@
   "scripts": {
     "test": "grunt test",
     "format": "standard --fix && prettier -l --write --single-quote --no-semi '**/*.{html,json,md}' && eslint '**/*.{html,md}' --fix",
+    "dist": "rm -rf dist/* && rollup -c",
     "release": "release-it"
   },
   "repository": {