chore: add license + rust build badges to README

Author: jvatic

README.md

@@ -1,6 +1,9 @@
 sql-schema
 ==========
 
+[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+[![Build Status](https://github.com/jvatic/sql-schema/actions/workflows/rust.yml/badge.svg?branch=main)](https://github.com/jvatic/sql-schema/actions?query=workflow%3ARust+branch%3Amain)
+
 This crate provides tools for generating schema migrations based on edits to a canonical schema file.
 
 ## Status