A rare case where readability and consistency may not be the same. (Let's not argue about this, it's subjective. I'm aware of the obvious counter- and counter-counter-arguments, such as syntax hilighting and greppability.)
Why not just settle permanently on double quotes? This is what Go and other languages did and I think it's a good idea.
While having choice of quotes reduces the need for escaping, most languages that provide it also still support escaping. E.g., Ruby has double-quoted strings with escaping, single-quotes without, %Q(...) with, %q(...) without, and two different heredoc forms, with and without escaping (the forms that allow escaping also support interpolation).
Well Lua is about 30 years old and Go is, what, 10 years old? I would expect a language that is barely a decade old to improve on past ideas and mistakes.