Not automatically until Arch moves it from the AUR into the repos, and it then arrives in Manjaro’s repos (unless the Manjaro team decide to add it to the repos themselves - very unlikely while it is still in development).
In the meantime, you should follow the regular advice provided here regarding AUR packages - rebuild it by running the pamac build kgamma2-git command again after doing a system update (especially if the update includes KDE/Plasma or Qt packages).
As the package is in the AUR, running pamac build kgamma2-git will download the PKGBUILD which contains the information required to build the package on your system, and then build the package for you.