Fixed link

README.md

@@ -2,4 +2,4 @@
 
 Here you can find my clumsy solutions to [Advent of Code 2021](https://adventofcode.com/2021) challenges.
 
-![Final score](https://raw.githubusercontent.com/pczajkowski/aoc2021/master/calendar.png "Calendar")
+![Final score](https://github.com/pczajkowski/aoc2021/blob/main/calendar.png "Calendar")