build: update library version to 6.2.0 to release changes in pull #297

lti_consumer/__init__.py

@@ -4,4 +4,4 @@ Runtime will load the XBlock class from here.
 from .apps import LTIConsumerApp
 from .lti_xblock import LtiConsumerXBlock
 
-__version__ = '6.1.0'
+__version__ = '6.2.0'