message: chore(readme): removed beta from bootstrap css link
diff: @@ -58,7 +58,7 @@ You will need bootstrap styles (Bootstrap 3)
  Or Bootstrap 4
  ```
  <!--- index.html -->
  -<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet">
  +<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet">
  ```
  To enable bootstrap 4 theme templates in ngx-bootstrap, please read
  [this](https://github.com/valor-software/ngx-bootstrap/blob/development/docs/getting-started/bootstrap4.md) .
  