fix: look for a .lua-format in the directory without permissions

[tqfx]

Procedure

~/tree/LuaFormatter $ uname -a
Linux localhost 4.14.141-ga540ec5 #1 SMP PREEMPT Thu Feb 18 12:35:08 CST 2021 aarch64 Android
~/tree/LuaFormatter $ pwd
/data/data/com.termux/files/home/tree/LuaFormatter
~/tree/LuaFormatter $ ls /data/data
ls: cannot open directory '/data/data': Permission denied
~/tree/LuaFormatter $ build/lua-format
terminating with uncaught exception of type std::__ndk1::__fs::filesystem::filesystem_error: filesystem error: in directory_iterator::directory_iterator(...): Permission denied [/data/data]
Aborted