Better sharing UX with nbgitpuller and contextual error handling

TL;DR nbgitpuller now has improved UX context-aware error handling. Update to version 1.3.0 and let us know what you think by opening an issue 🚀 What is nbgitpuller? nbgitpuller lets you distribute content to a Jupyter user via the click of a button! This allows your users to focus on the content without needing to understand git or other version control machinery. nbgitpuller provides automatic, opinionated conflict resolution by using git under the hood.