Adding CLIMATE-FEVER dataset
I `git rebase`ed my branch to `upstream/master` as suggested in point 7 of <https://huggingface.co/docs/datasets/share_dataset.html> and subsequently used `git pull` to be able to push to my remote branch. However, I think this messed up the history.

Please let me know if I should create a clean new PR with my changes.

Update: I also fixed the dataset name in the Dataset Card. Dear @SBrandeis , @lhoestq . I am not sure how to fix the PR with respect to the additional files that are currently included in the commits. Could you provide me with an example? Otherwise I would be happy to close/re-open another PR. Please let me know if anything is missing for the review. Hi @tdiggelm, thanks for the contribution! This dataset is really awesome.
I believe creating a new branch from master and opening a new PR with your changes is the simplest option since no review has been done yet. Feel free to ping us when it's done. > Hi @tdiggelm, thanks for the contribution! This dataset is really awesome.
> I believe creating a new branch from master and opening a new PR with your changes is the simplest option since no review has been done yet. Feel free to ping us when it's done.

Thank you very much for your quick reply! Will do ASAP and ping you when done. closing in favor of #1623
This PR request the addition of the CLIMATE-FEVER dataset:
A dataset adopting the FEVER methodology that consists of 1,535 real-world claims regarding climate-change collected on the internet. Each claim is accompanied by five manually annotated evidence sentences retrieved from the English Wikipedia that support, refute or do not give enough information to validate the claim totalling in 7,675 claim-evidence pairs. The dataset features challenging claims that relate multiple facets and disputed cases of claims where both supporting and refuting evidence are present.

More information can be found at:
- Homepage: <http://climatefever.ai>
- Paper: <https://arxiv.org/abs/2012.00614>

