Re: [voidlinux/void-packages] Python-3.6.2_1 update doesn't establish
/usr/bin/python3 symlink to python3.6 (#7521)
Had the same issue, @Duncaen already knows about it. A simple `xbps-alternatives -p python3 python3` fixes this.
xbps-alternatives -g python3 -s python3
$ ls -l /usr/bin/python
lrwxrwxrwx 1 root root 9 Aug 29 10:46 /usr/bin/python -> python2.7
$ ls -l /usr/bin/python3
lrwxrwxrwx 1 root root 9 Aug 29 10:46 /usr/bin/python3 -> python3.6
Reference: https://forum.voidlinux.eu/t/python3-gone-missing/3319/3?u=cardinal
`python3` alternatives group is gone.