Compilation error

```
[ 20%] Building C object CMakeFiles/dirbuster-ng.dir/src/dirbuster-ng.c.o
/Users/rockyou/Virtual Apps/dirbuster-ng/src/dirbuster-ng.c:15:7: error: 
      non-void function 'parse_arguments' should return a value [-Wreturn-type]
                                return;
                                ^
```
Changing `return;` to `return 0;` solves this problem.