fix: images not visible on npm

Author: tgpetrov

README.md

@@ -12,8 +12,9 @@ A [NativeScript](https://www.nativescript.org) plugin that provides ui elements
 - [API](#api)
 - [Contribute](#contribute)
 - [Get Help](#get-help)
-<img src="docs/date_picker_field.png" width="500px"/>
-<img src="docs/time_picker_field.png" width="500px"/>
+
+<img alt="DatePickerField on iOS (left) and Android (right)"  src="https://raw.githubusercontent.com/NativeScript/nativescript-datetimepicker/master/docs/date_picker_field.png" width="500px"/>
+<img alt="TimePickerField on iOS (left) and Android (right)" src="https://raw.githubusercontent.com/NativeScript/nativescript-datetimepicker/master/docs/time_picker_field.png" width="500px"/>
 
 ## Installation
 ```
@@ -100,7 +101,7 @@ The `TimePickerField` will determine whether to use 12 or 24 hour format (for fo
 
 You can use css to style the `DatePickerField` and the `TimePickerField`. The field itself can be styled just as every other `TextField`, additionally the picker supports changing of its colors through predefined css classes: `date-time-picker` (picker background and title text color), `date-time-picker-spinners` (background and text color of the date/time selecting spinners), `date-time-picker-buttons` (background and text color of the OK/Cancel buttons), `date-time-picker-button-ok` and `date-time-picker-button-cancel` (to provide a separate style for each button). Please note that the iOS native implementation has limited capabilities for the buttons background colors. When a button is marked as a Cancel button, its background is always white and can't be changed. If you really need a cancel button with another color, you can pass a background color through the designated cancel button class, however this will change the picker layout and place the cancel button along with the OK button and they will both have the same background color.
 
-<img src="docs/date_picker_field_css.png" width="500px"/>
+<img alt="DatePickerField with CSS applied on iOS (left) and Android (right)" src="https://raw.githubusercontent.com/NativeScript/nativescript-datetimepicker/master/docs/date_picker_field_css.png" width="500px"/>
 
 Here's the css used to achieve the above result, as used in the [demo](https://github.com/NativeScript/nativescript-datetimepicker/blob/master/demo/app/home/home-page.css#L9), [demo-angular](https://github.com/NativeScript/nativescript-datetimepicker/blob/master/demo-angular/src/app/home/home.component.css#L9) and [demo-vue](https://github.com/NativeScript/nativescript-datetimepicker/blob/master/demo-vue/app/components/Home.vue#L164) applications.