speakup: Add github repository URL and bug tracker

We have set up a repository for users to try newer releases more easily, and
keep records of known bugs.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20201222014756.ov5vi6fywylbp5n6@function


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>