Use Go 1.18 to build Docker images
Go 1.18 has now been released for a while and the CI already tests Dendrite with Go 1.18
so there should be no issues. Go 1.18 brings some performance improvements for ARM via
the register calling convention so it makes sense to switch to it.
MODIFY
build/docker/Dockerfile.monolith
build/docker/Dockerfile.monolith
-FROM docker.io/golang:1.17-alpine AS base
+FROM docker.io/golang:1.18-alpine AS base
RUN apk --update --no-cache add bash build-base

MODIFY
build/docker/Dockerfile.polylith
build/docker/Dockerfile.polylith
-FROM docker.io/golang:1.17-alpine AS base
+FROM docker.io/golang:1.18-alpine AS base
RUN apk --update --no-cache add bash build-base

Use Go 1.18 to build Docker images (#2391)

Go 1.18 has now been released for a while and the CI already tests Dendrite with Go 1.18
so there should be no issues. Go 1.18 brings some performance improvements for ARM via
the register calling convention so it makes sense to switch to it.