Re-enable breaking change detection

[brentru]

We've disabled buf's breaking change detection while developing the protobufs. Let's re-enable these once the repository is finalized.

Locations:

• https://github.com/brentru/blinkaconnect-protobuf/blob/master/buf.yaml#L10
• https://github.com/brentru/blinkaconnect-protobuf/blob/master/Makefile#L81
• https://github.com/brentru/blinkaconnect-protobuf/blob/master/Makefile#L89
• https://github.com/brentru/blinkaconnect-protobuf/blob/master/Makefile#L98