Finnish was missing from the other languages list (#3480)

README.md

@@ -33,6 +33,7 @@ Please read [CONTRIBUTING](/CONTRIBUTING.md). If you're new to Github, [welcome]
 + [Czech](/free-programming-books-cs.md)
 + [Dutch](/free-programming-books-nl.md)
 + [English](/free-programming-books.md)
++ [Finnish](/free-programming-books-fi.md)
 + [French](/free-programming-books-fr.md)
 + [German](/free-programming-books-de.md)
 + [Greek](/free-programming-books-gr.md)