Bump ruby from 2.6.4-alpine to 2.7.0-alpine
Bump ruby from 2.6.4-alpine to 2.7.0-alpine

Bumps ruby from 2.6.4-alpine to 2.7.0-alpine.

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
nerab/pinboard-fixup-github-titles,nerab/pinboard-fixup-github-titles