Update alpine image to Alpine Linux 3.15

[danopia]

trafficstars

This moves from an 8-month-old base to a 4-month-old base.

Fixes #197

Note that Alpine Linux 3.14 introduced use of the faccessat2 syscall, which caused some incompatibilities with Docker versions before Docker 20.10.0 when running particular programs such as ruby or make. More details in the changelog.

[CLAassistant]

All committers have signed the CLA.

[captn3m0]

3.16 is now released: https://alpinelinux.org/posts/Alpine-3.16.0-released.html and avilable https://hub.docker.com/r/frolvlad/alpine-glibc/tags as well.

[danopia]

3.16 is now released

Thanks, updated PR.

[danopia]

Error relocating /tini: __fprintf_chk: symbol not found

Looks like there's going to be some further work for Alpine 3.16, I'll revert this PR 🥲 thanks CI

[crowlKats]

Closing in favour of #262