refactor(@angular/cli): name entry point function

Internal tooling does not like anonymous externs, failing the g3 syncing process: http://sponge2/30b47d1d-0607-425c-bd78-8d5a63af3f2f

Author: dgp1130

packages/angular/cli/index.d.ts

@@ -16,4 +16,4 @@ export declare class Version {
 
 export declare const VERSION: Version;
 
-export default function (options: { cliArgs: string[] }): Promise<number>;
+export default function execute(options: { cliArgs: string[] }): Promise<number>;

packages/angular/cli/lib/cli/index.ts

@@ -18,7 +18,7 @@ import { isNodeVersionMinSupported, supportedNodeVersions } from '../../src/util
 export { VERSION } from '../../src/utilities/version';
 
 /* eslint-disable no-console */
-export default async function (options: { cliArgs: string[] }) {
+export default async function execute(options: { cliArgs: string[] }) {
   // This node version check ensures that the requirements of the project instance of the CLI are met
 
   if (!isNodeVersionMinSupported()) {