Update README.md to contain ISO Codes for available languages

Sources:

Hugging Face: https://huggingface.co/languages
Wiki: https://en.wikipedia.org/wiki/Phom_language
Glottolog: https://glottolog.org/resource/languoid/id/phom1236

README.md

@@ -17,7 +17,7 @@ dataset_info:
     num_bytes: 405870.6
     num_examples: 2043
   download_size: 1232348
-  dataset_size: 2029353.0
+  dataset_size: 2029353
 configs:
 - config_name: default
   data_files:
@@ -25,4 +25,7 @@ configs:
     path: data/train-*
   - split: test
     path: data/test-*
----
+language:
+- en
+- nph
+---