message: fix: correct usage of execa
diff: // tslint:disable:no-implicit-dependencies
  import test from 'ava';
  -import { shell } from 'execa';
  +import execa from 'execa';
  import * as fs from 'fs';
  function normalize(input: string): string {
  @@ -12,8 +12,8 @@ function normalize(input: string): string {
  test('cli should read from stdin', async t => {
  const expected = fs.readFileSync('./tests/import-react-component.d.ts').toString();
  - const result = await shell(
  - `cat ./tests/import-react-component.jsx |${process.argv[0]} ./cli.js --module-name component`);
  + const result = await execa(
  + `cat ./tests/import-react-component.jsx |${process.argv[0]} ./cli.js --module-name component`, {shell: true});
  t.is(normalize(result.stdout), normalize(expected));
  });
  @@ -21,8 +21,8 @@ test('cli should read from stdin', async t => {
  test('cli should read from file', async t => {
  const expected = fs.readFileSync('./tests/import-react-component.d.ts').toString();
  - const result = await shell(
  - `${process.argv[0]} ./cli.js --module-name component --file ./tests/import-react-component.jsx`);
  + const result = await execa(
  + `${process.argv[0]} ./cli.js --module-name component --file ./tests/import-react-component.jsx`, {shell: true});
  t.is(normalize(result.stdout), normalize(expected));
  });
  