Attribute selector doesn't work on attributes that have numbers in them

[ghost]

In ShallowTraversal.js the selector for the attribute doesn't work on attributes that have numbers in them.
const propKey = selector.split(/\[([a-zA-Z-]*?)(=|])/)[1];

Instead, it should be:
const propKey = selector.split(/\[([a-zA-Z-0-9-]*?)(=|])/)[1];

[ljharb]

@raduanastases it'd be great if you could file a PR with a test case!

[ljharb]

(also, please note that attributes that start with numbers are invalid)

[ghost]

sure, I'll get to it as soon as possible.

[jsmey]

I made this change and added a test. PR #700

[ljharb]

Closed in #1086