Update README.md (#7000)

README.md

@@ -151,6 +151,7 @@ This project lists books and other resources grouped by genres:
 + [Russian / Русский язык](courses/free-courses-ru.md)
 + [Sinhala / සිංහල](courses/free-courses-si.md)
 + [Spanish / español / castellano](courses/free-courses-es.md)
++ [Tamil / தமிழ்](courses/free-courses-ta.md)
 + [Thai / ภาษาไทย](courses/free-courses-th.md)
 + [Turkish / Türkçe](courses/free-courses-tr.md)
 + [Ukrainian / Українська](courses/free-courses-uk.md)