Fixed date.

Author: janpgit

docs/index.html

@@ -160,7 +160,7 @@ <h2><a name="final_assignment">Final Lab Assignment</a></h2>
 The first phase of the shell assignment must be finished and handed over to us
 via e-mail before the end of the Winter semester, ie. <b>Sunday 23:59, January
 9, 2022, CET</b>.  You need to send the e-mail before the deadline. If for any
-reason the Winter semester is prolonged then January 10 still stands unless
+reason the Winter semester is prolonged then January 9 still stands unless
 announced otherwise.
 
 <p>The second phase must be finished and handed over to us via e-mail before the