Update the read me file in the master branch to include the old plain well-known version

[mhewedy]

Upload the version in this git revision https://github.com/superduper/BrightnessMenulet/tree/c423bff4983c6d9436fcbf92b66056715a1cc40b to the master branch and point to it, so old users can use the old that was working fine (until you fix the new version)