fix: use npm install (#77)

node_modules/undici/lib/mock/pluralizer.js

@@ -0,0 +1,29 @@
+'use strict'
+
+const singulars = {
+  pronoun: 'it',
+  is: 'is',
+  was: 'was',
+  this: 'this'
+}
+
+const plurals = {
+  pronoun: 'they',
+  is: 'are',
+  was: 'were',
+  this: 'these'
+}
+
+module.exports = class Pluralizer {
+  constructor (singular, plural) {
+    this.singular = singular
+    this.plural = plural
+  }
+
+  pluralize (count) {
+    const one = count === 1
+    const keys = one ? singulars : plurals
+    const noun = one ? this.singular : this.plural
+    return { ...keys, count, noun }
+  }
+}