#### Describe the bug

Upgrading from version 0.21.4 to 0.22.0 fails to compile a TypeScript app.

#### To Reproduce

Have a code that looks like this

```ts
import axios from 'axios';

const func = () => {
  delete axios.defaults.headers.common.Authorization;
}
```

Request responses are also incorrectly inferred after this update. Instead of `any`, data will be set to `Params`.

```ts
import axios from 'axios';

export const request = async (params: Params): Promise<Response> => {
  const { data } = await axios.put('urlPath', params);
  return data;
};
```

#### Expected behavior

There should be no breaking changes as change log doesn't mention them.

#### Environment
 - Axios Version [e.g. 0.18.0] 0.22.0
 - Adapter [e.g. XHR/HTTP] -
 - Browser [e.g. Chrome, Safari] -
 - Browser Version [e.g. 22] -
 - Node.js Version [e.g. 13.0.1] -
 - OS: [e.g. iOS 12.1.0, OSX 10.13.4] -
 - Additional Library Versions [e.g. React 16.7, React Native 0.58.0] React 17.0.2

#### Additional context/Screenshots
Add any other context about the problem here. If applicable, add screenshots to help explain.

test/typescript/axios.ts
} from '../../';
const config: AxiosRequestConfig = {
  url: '/user',
  method: 'get',
  baseURL: 'https://api.example.com/',
  transformRequest: (data: any) => '{"foo":"bar"}',
  transformResponse: [
    (data: any) => ({ baz: 'qux' })
  ],
  headers: { 'X-FOO': 'bar' },
  params: { id: 12345 },
  paramsSerializer: (params: any) => 'id=12345',
  data: { foo: 'bar' },
  timeout: 10000,
  withCredentials: true,
  auth: {
    username: 'janedoe',
    password: 's00pers3cret'
  },
  responseType: 'json',
  xsrfCookieName: 'XSRF-TOKEN',
  xsrfHeaderName: 'X-XSRF-TOKEN',
  onUploadProgress: (progressEvent: ProgressEvent) => {},
  onDownloadProgress: (progressEvent: ProgressEvent) => {},
  maxContentLength: 2000,
  maxBodyLength: 2000,
  validateStatus: (status: number) => status >= 200 && status < 300,
  maxRedirects: 5,
  proxy: {
    host: '127.0.0.1',