OpenSLR 25: ASR data for Amharic, Swahili and Wolof
Whoever handles this just needs to: 

- [ ] fork the HuggingFace Datasets repo
- [ ] update the [existing dataset script](https://github.com/huggingface/datasets/blob/master/datasets/openslr/openslr.py) to add SLR25. Lots of copypasting from other sections of the script should make that easy. 
Amharic URL: https://www.openslr.org/resources/25/data_readspeech_am.tar.bz2. 
Swahili URL: https://www.openslr.org/resources/25/data_broadcastnews_sw.tar.bz2, 
Wolof URL: https://www.openslr.org/resources/25/data_readspeech_wo.tar.bz2
- [ ] update the [data card](https://github.com/huggingface/datasets/blob/master/datasets/openslr/README.md) to include information about SLR25. There's lots of other examples to draw from. 
- [ ] add the appropriate language tags to the data card as well. https://www.w3.org/International/questions/qa-choosing-language-tags, or just use `sw`, `am`, and `wo` for consistency. 
- [ ] make a pull request to merge your changes back into HuggingFace's repo ... also the example in "use in datasets library" should be updated. It currently says 
![image](https://user-images.githubusercontent.com/4109253/135115980-8583a44a-cae6-4121-b699-00667020849f.png)
But you actually have to specify a subset, e.g. 
```python
dataset = load_dataset("openslr", "SLR32")
``` ![image](https://user-images.githubusercontent.com/4109253/135116070-82d4e732-b7b3-4c5b-bd4e-a40d8ccabb0e.png)


## Adding a Dataset
- **Name:** *SLR25*
- **Description:** *Subset 25 from OpenSLR. Other subsets have been added to https://huggingface.co/datasets/openslr, 25 covers Amharic, Swahili and Wolof data*
- **Paper:** *https://www.openslr.org/25/ has citations for each of the three subsubsets. *
- **Data:** *Currently the three links to the .tar.bz2 files can be found a thttps://www.openslr.org/25/*
- **Motivation:** *Increase ASR data for underrepresented African languages. Also, other subsets of OpenSLR speech recognition have been uploaded, so this would be easy.*


https://github.com/huggingface/datasets/blob/master/datasets/openslr/openslr.py already has been created for various other OpenSLR subsets, this should be relatively straightforward to do. 

