Bump alpine from 3.18 to 3.20 in /protobuf#321

dependabot[bot] wants to merge 2 commits intomainopen-telemetry/build-tools:mainfrom

dependabot/docker/protobuf/alpine-3.20open-telemetry/build-tools:dependabot/docker/protobuf/alpine-3.20Copy head branch name to clipboard