point to example MLM v1.2.0 model metadata and artifacts on huggingface

[rbavery]

Description

This updates the READMe to remove two TODOs: provides examples of MLM v1.2.0 and artifacts that we use at Wherobots and also updates the JSON schema link to match the repo description.

Related Issue

addresses #25

Type of Change

• 📚 Examples, docs, tutorials or dependencies update;
• 🔧 Bug fix (non-breaking change which fixes an issue);
• 🥂 Improvement (non-breaking change which improves an existing feature);
• 🚀 New feature (non-breaking change which adds functionality);
• 💥 Breaking change (fix or feature that would cause existing functionality to change);
• 🔐 Security fix.

Checklist

• I've read the CONTRIBUTING.md guide;
• I've updated the code style using make check;
• I've written tests for all new methods and classes that I created;
• I've written the docstring in Google format for all the methods and classes that I used.