Use pyiterable over undatum

[amotl]

About

It looks like some functionality has been migrated from undatum to pyiterable. @ivbeg told us about it over here:

• ModuleNotFoundError: No module named 'chardet' datacoon/undatum#37 (comment)

Thanks!

Action

Reflect the code migration in this codebase. 🍀

References

• https://github.com/crate/cratedb-toolkit/actions/runs/20220083793/job/58040375181?pr=584#step:6:92