Fix readme issues

Author: justanr

README.md

@@ -43,7 +43,7 @@ schema.dump({'light_color': EnumField.red}).data
 # {'light_color': 'red'}
 
 schema.load({'light_color': 'red'}).data
-# {'light_color': EnumField.red}
+# {'light_color': StopLight.red}
 ```
 
 ### Customizing loading and dumping behavior

setup.py

@@ -19,11 +19,12 @@
 if __name__ == '__main__':
     setup(
         name='marshmallow-enum',
-        version='1.5.0',
+        version='1.5.1',
         author='Alec Nikolas Reiter',
         author_email='[email protected]',
         description='Enum field for Marshmallow',
         long_description=readme + '\n\n' + changelog,
+        long_description_content_type="text/markdown",
         package_data={'': ['LICENSE', 'README.md', 'CHANGELOG']},
         include_package_data=True,
         license='MIT',