Add Dengue dataset in Filipino
This PR adds the Dengue Dataset, a benchmark dataset for low-resource multiclass classification, with 4,015 training, 500 testing, and 500 validation examples, each labeled as part of five classes. Each sample can be a part of multiple classes. Collected as tweets.

Link to the paper: https://ieeexplore.ieee.org/document/8459963

Link to the dataset/repo: https://github.com/jcblaisecruz02/Filipino-Text-Benchmarks
