maintain YAML structure reading from README

[bhavitvyamalik]

How YAML used be loaded earlier in the string (structure of YAML was affected because of this and YAML for datasets with multiple configs was not being loaded correctly):

annotations_creators:
labeled_final:
- expert-generated
labeled_swap:
- expert-generated
unlabeled_final:
- machine-generated
language_creators:
- machine-generated
languages:
- en
licenses:
- other
multilinguality:
- monolingual
size_categories:
labeled_final:
- 10K<n<100K
labeled_swap:
- 10K<n<100K
unlabeled_final:
- 100K<n<1M
source_datasets:
- original
task_categories:
- text-classification
- text-scoring
task_ids:
- semantic-similarity-classification
- semantic-similarity-scoring
- text-scoring-other-paraphrase-identification

How YAML is loaded in string now:

annotations_creators:
  labeled_final:
  - expert-generated
  labeled_swap:
  - expert-generated
  unlabeled_final:
  - machine-generated
language_creators:
- machine-generated
languages:
- en
licenses:
- other
multilinguality:
- monolingual
size_categories:
  labeled_final:
  - 10K<n<100K
  labeled_swap:
  - 10K<n<100K
  unlabeled_final:
  - 100K<n<1M
source_datasets:
- original
task_categories:
- text-classification
- text-scoring
task_ids:
- semantic-similarity-classification
- semantic-similarity-scoring
- text-scoring-other-paraphrase-identification

[lhoestq]

Thanks !