rclnodejs v0.20.0

Feature

• LifecycleNode constructor missing enableCommunicationInterface parameter added in ROS2 Galactic #799
• add new example: ros-graph-example #803

Bug Fix

• Fixes gcc 'unused variable warning' on lifecycle_bindings.cpp #806

Others

• Hide npm warnings during installation; set loglevel='error' #807
• Efficiency tips doc #804
• Improved jsdoc for Node ros graph methods, eg. getServiceNamesAndTypes() #802
• add .gitattributes to project #801
• Wrong format of npmjs-readme.md #797