s6-linux-init: bump version to 0.3.1.1

s6-linux-init: bump version to 0.3.1.1

Fixes:

- http://autobuild.buildroot.net/results/7208b2630832c3293db39affd7886691691770b4
- http://autobuild.buildroot.net/results/c10548ffde2d83b6298759793ef99a5142309678
- http://autobuild.buildroot.net/results/a0da44d547670bc46479980ac1b29e7e2421b378
- http://autobuild.buildroot.net/results/df7ec3facb183b7caf1a6eaff4f89a65961681fb
- http://autobuild.buildroot.net/results/fe7a32fbec5d64c359ad0326a01764a631dcc6f6
- http://autobuild.buildroot.net/results/79029d736910ca32567bc8a82ac6982c3ac1e1fb
- http://autobuild.buildroot.net/results/20091ae932385bd7ba4205626bce174e385da221
- http://autobuild.buildroot.net/results/c1cd69444abb32e77928e7d7363f5cdfea79dcf5

Signed-off-by: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>