[GearSwap] Change exported filename format for accessibility

[nekonok]

When we execute gs export, we get a file named like Character 12 50 47PM 16-22-05.lua.
But it's hard to find because they can not be sorted with datetime by filenames.
And this date format is not familiar to JP users.

So I suggest to use RFC3339 date format like 2001-02-03 04:05:06+09:00 (Timezone is unnecessary).

Source: https://github.com/Windower/Lua/blob/dev/addons/GearSwap/export.lua#L171

        path = path..os.date(' %H %M %S%p  %y-%d-%m')