README.adoc: change suggested sort to version sort

The reason is that compared to default settings of sort version sort is
going to sort correctly numbers. As an exalple:
1.1, 1.2, 1.12
should be sorted as stated here byt sorf possibly sortes it as:
1.1, 1.12, 1.2

README.adoc

@@ -26,7 +26,7 @@ Turris OS fixup releases.
 
 It is advised to build the latest release version as with that you are most likely
 to get to the end. To get latest version you can do:
-`git checkout $(git tag | sort | tail -1)`.
+`git checkout "$(git tag | sort -V | tail -1)"`.
 
 Requirements
 -------------