readme: relative symlink

README.md

@@ -5,5 +5,5 @@
 ```sh
 sudo apt-get install latexmk zathura
 git clone git@git.hammerle.me:fphammerle/config-latexmk.git ~/.config/latexmk
-ln --symbolic --backup=numbered ~/.config/latexmk/latexmkrc ~/.latexmkrc
+ln --symbolic --backup=numbered .config/latexmk/latexmkrc ~/.latexmkrc
 ```