[semconvgen] Feature Request: Add option to disable attribute id regex validation

[wperron]

Hey folks 👋 We have existing code that emits attributes with IDs that do not match the semconv regex (for example, some of them are pascal case). We want to use the semconvgen tool with a custom template, but ideally we would like to be able to disable the regex validation on the attribute IDs as an option flag for semconvgen. In our case, relabelling would be too long/costly as we have a huge codebase in multiple languages to comb through.