Bump github.com/prometheus/client_golang from 1.12.1 to 1.12.2#1

dependabot[bot] wants to merge 1 commit intomasterMicroOps-cn/alertmanager:masterfrom

dependabot/go_modules/github.com/prometheus/client_golang-1.12.2MicroOps-cn/alertmanager:dependabot/go_modules/github.com/prometheus/client_golang-1.12.2Copy head branch name to clipboard