fix(deps): remove stubbed strip-ansi typings, use default import

In version 5.2.0 strip-ansi ships its own typings.

Author: unstubbable

tests/error-reporting-test.ts

@@ -1,6 +1,6 @@
 // tslint:disable:no-implicit-dependencies
 import test from 'ava';
-import * as stripAnsi from 'strip-ansi';
+import stripAnsi from 'strip-ansi';
 
 import * as react2dts from '../src/index';