message: chore(docs): update readme
  fixed a typo
diff: @@ -44,7 +44,7 @@ Or Bootstrap 4
  <!--- index.html -->
  <link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet">
  ```
  -Hot to enable bootstrap 4 theme templates in ng2-bootstrap, please read
  +To enable bootstrap 4 theme templates in ng2-bootstrap, please read
  [here](https://github.com/valor-software/ng2-bootstrap/blob/development/docs/getting-started/bootstrap4.md)
  ```
  