Introduced alpine-slim image variant.

Dockerfile-alpine-slim.template

generate-stackbrew-library.sh

mainline/alpine-slim/10-listen-on-ipv6-by-default.sh

mainline/alpine-slim/20-envsubst-on-templates.sh

mainline/alpine-slim/30-tune-worker-processes.sh

mainline/alpine-slim/Dockerfile

mainline/alpine-slim/docker-entrypoint.sh

stable/alpine-slim/10-listen-on-ipv6-by-default.sh

stable/alpine-slim/20-envsubst-on-templates.sh

stable/alpine-slim/30-tune-worker-processes.sh

stable/alpine-slim/Dockerfile

stable/alpine-slim/docker-entrypoint.sh

update.sh