D5747: add pid to plasma window management protocol

[Eike Hein]

hein accepted this revision.

REPOSITORY
  R127 KWayland

REVISION DETAIL
  https://phabricator.kde.org/D5747

To: sebas, #plasma, hein, graesslin
Cc: apol, davidedmundson, plasma-devel, #frameworks, ZrenBot, spstarr, 
progwolff, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, lukas