feat: create etymolgies endpoint

lib/word/etymologies.js

@@ -0,0 +1,29 @@
+import { Wordnik } from '../mod'
+
+/**
+ * Etymologies
+ * @param {string} word
+ * @param {*} options
+ * @param {boolean} [useCanonical=false]
+ * @returns {json} response
+ */
+export async function etymologies(word, {
+	useCanonical
+}) {
+	if (!word) throw new Error('word is required')
+	const wordnik = new Wordnik('word.json/' + word + '/etymologies')
+	let endpoint =
+		wordnik.base + wordnik.version + wordnik.target
+
+	if (useCanonical) {
+		if (!(typeof useCanonical === 'boolean')) {
+			throw new Error('"useCanonical" must be a boolean')
+		}
+		endpoint = endpoint + '&' + 'useCanonical=' + useCanonical
+	}
+
+	endpoint = endpoint + '&' + wordnik.key
+	const response = await fetch(endpoint)
+
+	return await response.json()
+}