Fix NonMatchingChecksumError in mbpp dataset
_The documentation is not available anymore as the PR was closed or merged._ Thank you for the quick response! Before noticing that you already had implemented the fix, I already had implemened my own version. I'd also suggest bumping the major version because the contents of the dataset changed, even if only slightly.
I'll attach my version of the affected files: [mbpp-checksum-changes.zip](https://github.com/huggingface/datasets/files/9258161/mbpp-checksum-changes.zip). Hi @stadlerb, thanks for your feedback.

We normally update the major version whenever there is a new dataset release, usually with a breaking change in schema. The patch version is updated whenever there is a small correction in the dataset that does not change its schema.

As a side note for future contributions, please note that this dataset is hosted in our library GitHub repository. Therefore, the PRs to GitHub-hosted datasets needs being done through GitHub.

Currently added datasets are hosted on the Hub and for them, PRs can be done through the Hub. I just noticed another problem with the dataset: The [GitHub page](https://github.com/google-research/google-research/tree/master/mbpp) and the [paper](http://arxiv.org/abs/2108.07732) mention a train-test split, which is not reflected in the dataloader. I'll open a new issue regarding this later.
Fix issue reported on the Hub: https://huggingface.co/datasets/mbpp/discussions/1

Fix #4787. 