Automatically update bundlesizeMax on publish

**Is your feature request related to a problem? Please describe.**

People frequently forget to update the `bundlesizeMax` parameter in `.aegir.js`, it'd be helpful if we could just do that automatically when publishing.

**Describe the solution you'd like**

The addition of a flag to `aegir release*` that updates `bundlesizeMax`.

**Describe alternatives you've considered**

Manual updating of this value is often forgotten.

**Additional context**

🤷