fix(cli): use lowercase version option

README.md

@@ -59,7 +59,7 @@ options:
                     none (default: paru, else yay, when installed; other backends ignore it)
   --no-aur          same as --aur-helper=none
   -h, --help        this help
-  -V, --version     print the version
+  -v, --version     print the version
 ```
 
 Exit status: `0` ok, `1` usage or backend error, `2` aborted (end of input),