Update rockspec for LuaOauth to support 5.3

[FuriouslyCurious]

Hi Ignacio,

The current rockspec doesn't support 5.3 and when trying to install it, it falls back on much older versions of dependencies.

Can you please update the rockspec to current versions? Thanks!

[ignacio]

The thing is that I still depend on LuaCrypto, which does not yet support Lua 5.3. Probably should start using a different library.