update skarnet.org packages

skalibs:           2.4.7.0 -> 2.3.9.0
execline:          2.1.4.0 -> 2.1.4.5
s6:                2.2.1.0 -> 2.2.4.3
s6-rc:             0.0.1.0 -> 0.0.2.1
s6-portable-utils: 2.0.5.2 -> 2.0.5.3
s6-linux-utils:    2.0.2.0 -> 2.0.2.3
s6-dns:            2.0.0.4 -> 2.0.0.7
s6-networking:     2.1.0.1 -> 2.1.0.4