Issue #3458705 - Update readme

Closes #3458705

README.md

+# Conditional Stylesheets
+
+Internet Explorer implements a proprietary technology called Conditional
+Comments. While web developers frown upon technologies that aren't cross-browser
+supported, many CSS developers have found Conditional Comments very useful since
+they can be used to fix the rendering of CSS in IE by placing IE-only CSS inside
+conditional comments.
+
+This module allows themes to easily add conditional stylesheets to the theme's
+.info.yml file.
+
+For a full description of the module, visit the
+[project page](https://www.drupal.org/project/conditional_styles).
+
+To submit bug reports and feature suggestions, or track changes in the
+[issue queue](https://www.drupal.org/project/issues/conditional_styles).
+
+
+## Table of contents
+
+- Requirements
+- Installation
+- Configuration
+- Maintainers
+
+
+## Requirements
+
+This module requires no modules outside of Drupal core.
+
+
+## Installation
+
+Install as you would normally install a contributed Drupal module. For further
+information, see
+[Installing Drupal Modules](https://www.drupal.org/docs/extending-drupal/installing-drupal-modules).
+
+
+## Configuration
+
+Add conditional styles via 'conditional-stylesheets' property in your *.info.yml of the theme.
+
+
+## Maintainers
+
+- John Albin Wilkins - [JohnAlbin](https://www.drupal.org/u/johnalbin)
+- Viktor Holovachek - [AstonVictor](https://www.drupal.org/u/astonvictor)