Update gitignore (sorry)

electron/node_modules/make-fetch-happen/lib/cache/errors.js

@@ -0,0 +1,11 @@
+class NotCachedError extends Error {
+  constructor (url) {
+    /* eslint-disable-next-line max-len */
+    super(`request to ${url} failed: cache mode is 'only-if-cached' but no cached response is available.`)
+    this.code = 'ENOTCACHED'
+  }
+}
+
+module.exports = {
+  NotCachedError,
+}