Update README dbt url

[maxsumrall]

Links now to the dbt-core open-source project: https://github.com/dbt-labs/dbt-core , instead of linking to getdbt.com

Copy of README.md for review:

dbt-score

What is dbt-score?

dbt-score is a linter for dbt model metadata.

dbt (Data Build Tool) is a great framework for creating, building, organizing, testing and documenting data
models, i.e. data sets living in a database or a data warehouse. Through a declarative approach, it allows data
practitioners to build data with a methodology inspired by software development practices.

This leads to data models being bundled with a lot of metadata, such as documentation, data tests, access control
information, column types and constraints, 3rd party integrations... Not to mention any other metadata that
organizations need, fully supported through the meta parameter.

At scale, with hundreds or thousands of data models, all this metadata can become confusing, disparate, and
inconsistent. It's hard to enforce good practices and maintain them in continuous integration systems. This is
wheredbt-score plays its role: by allowing data teams to programmatically define and enforce metadata rules, in an
easy and scalable manner.

Documentation

Everything you need (and more) can be found in
dbt-score documentation website.

Contributing

Would you like to contribute to dbt-score? That's great news! Please follow
the guide on the documentation website.
🚀

[matthieucan]

Thanks! 🚀