Bump alpine from 3.20 to 3.21 #2238

Job	Run time
Test and deploy (1.23, ubuntu-latest)	14m 47s
Test and deploy (1.23, ubuntu-latest)	14m 47s
Test and deploy Windows	19m 1s
Test and deploy Windows	19m 1s
Test and deploy (1.23, macos-latest)	12m 57s
Test and deploy (1.23, macos-latest)	12m 57s
golangci-lint	1m 53s
golangci-lint	1m 53s
Build Linux packages (amd64, ubuntu:18.04, latest, amd64)	1m 58s
Build Linux packages (amd64, ubuntu:18.04, latest, amd64)	1m 58s
Build Linux packages (aarch64, ubuntu18.04, latest, arm64)	16m 33s
Build Linux packages (aarch64, ubuntu18.04, latest, arm64)	16m 33s
Build Linux packages (ppc64le, ubuntu18.04, latest, ppc64le)	16m 11s
Build Linux packages (ppc64le, ubuntu18.04, latest, ppc64le)	16m 11s
Test build flags	18s
Test build flags	18s
Build Linux packages (armv7, ubuntu18.04, latest, arm7)	18m 18s
Build Linux packages (armv7, ubuntu18.04, latest, arm7)	18m 18s
Test with PgSQL/MySQL/Cockroach	20m 2s
Test with PgSQL/MySQL/Cockroach	20m 56s
	4h 4m 50s

Provide feedback