Update badges and add donate link to readme [skip ci]

Author: pinepain

README.md

@@ -1,10 +1,15 @@
 # Weak-referenced data structures for PHP based on Ref php extension
 
-[![Build Status](https://travis-ci.org/pinepain/php-object-maps.svg)](https://travis-ci.org/pinepain/php-object-maps)
-[![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/pinepain/php-object-maps/badges/quality-score.png)](https://scrutinizer-ci.com/g/pinepain/php-object-maps)
-[![Code Coverage](https://scrutinizer-ci.com/g/pinepain/php-object-maps/badges/coverage.png)](https://scrutinizer-ci.com/g/pinepain/php-object-maps)
+[![Build Status](https://travis-ci.org/pinepain/php-object-maps.svg?branch=master)](https://travis-ci.org/pinepain/php-object-maps)
+[![Build Status](https://travis-ci.org/pinepain/php-object-maps.svg?branch=master)](https://travis-ci.org/pinepain/php-object-maps)
+[![Code Coverage](https://scrutinizer-ci.com/g/pinepain/php-object-maps/badges/coverage.png?b=refactor)](https://scrutinizer-ci.com/g/pinepain/php-object-maps/?branch=refactor)
 [![SensioLabsInsight](https://insight.sensiolabs.com/projects/72be40cb-1d0f-48db-b89c-c99ea007bf63/mini.png)](https://insight.sensiolabs.com/projects/72be40cb-1d0f-48db-b89c-c99ea007bf63)
 
+### PLEASE READ:
+
+Maintaining this project takes significant amount of time and efforts.
+If you like my work and want to show your appreciation, please consider supporting me at https://www.patreon.com/pinepain.
+
 ## Requirements
 
  - PHP >= 7.1