Update citation to Hugging Face canonical URL

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -124,7 +124,7 @@ You are free to share and adapt the data for any purpose, including commercial u
 ```
 TRAI India Telecom Subscription Dataset (2016–2026).
 Compiled from TRAI Telecom Subscription Data PDF reports.
-https://github.com/rahulmatthan/india-telecom-data
+https://huggingface.co/datasets/rahulmatthan/india-telecom-data
 CC BY 4.0
 ```