Update setup.py

Author: igortavtib

setup.py

@@ -8,7 +8,7 @@
 setup(name='robotframework-appiumflutterlibrary',
       version='1.0.0-beta',
       description='Robot Framework Mobile flutter app testing library for Appium Client Android & iOS & Web',
-      long_description=open(join(ROOT, 'README.md')).read(),
+      long_description=open(join(ROOT, 'README.rst')).read(),
       author='Igor Augusto',
       author_email='igortavtib@gmail.com',
       url='https://github.com/igortavtib/robotframework-appiumflutterlibrary',