Update triggers to prevent tarball CI from running on 6.0.3xx and 6.0.4xx#14896

MichaelSimons merged 1 commit intodotnet:release/6.0.3xxdotnet/installer:release/6.0.3xxfrom

MichaelSimons:sb-6.0.3xx-triggersMichaelSimons/installer:sb-6.0.3xx-triggersCopy head branch name to clipboard