`examples/generated-files` is missing `Cargo.lock`

[mgorny]

Compared to other examples / test packages, examples/generated-files does not feature a Cargo.lock file. This is making it hard to consistently lock dependencies across all the examples.

[davidhewitt]

This was somewhat an innocent omission, looks like I left a .gitignore for Cargo.lock from #388 but then made some other changes.

#601 will fix. Is this a problem enough that you need a patch release for it? Or can it wait to ship whenever 1.14 does (probably a number of months away).

[mgorny]

Thanks. No release needed.

[davidhewitt]

Sure thing. Thanks for the report!