doc(README): bump cross-compiler version to 4.8.2

[skip ci]
fix(lua): cygwing compilation problem

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(lua): cpplint.py does not like multiline strings

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
chore(cmake/Modules/FindLua): disable TRY_RUN in cross-compilation.