Remove CUCUMBER_PUBLISH_TOKEN validation

[aslakhellesoy]

The PublishTokenParser only allows tokens that look like a base64-encoded string. Token validation should only be the server's responsibility. We don't actually want it to be a base64-encoded string, just a UUID.

@mpkorstanje do you remember why we added this?

[mpkorstanje]

Garbage in protection. Caching errors early is better in general. Rather then removing the validation you can expand the validation regex to include UUID like values too.

[aslakhellesoy]

We don't want to commit to any particular format for authentication tokens. We want to have the flexibility to change this on the server without needing to make a new release of Cucumber-JVM.

The server needs to validate the token anyway, so the only benefit of client validation is early errors for users.

The price of that benefit is too high: Not being able to change the token validation on the server without also having to make a new release of Cucumber-JVM.

[mpkorstanje]

Fair enough. Removing it won't break anything.