chore(docker): use golang tag so renovate maintains it (#4433)

Dockerfile

@@ -2,7 +2,7 @@
 # what distro is the image being built for
 ARG ALPINE_TAG=3.19.1@sha256:c5b1261d6d3e43071626931fc004f70149baeba2c8ec672bd4f27761f8e1ad6b
 ARG DEBIAN_TAG=12.5-slim@sha256:3d5df92588469a4c503adbead0e4129ef3f88e223954011c2169073897547cac
-ARG GOLANG_VERSION=1.22.1
+ARG GOLANG_TAG=1.22.1-alpine
 
 # renovate: datasource=github-releases depName=hashicorp/terraform versioning=hashicorp
 ARG DEFAULT_TERRAFORM_VERSION=1.8.0
@@ -13,7 +13,7 @@ ARG DEFAULT_CONFTEST_VERSION=0.49.1
 
 # Stage 1: build artifact and download deps
 
-FROM golang:${GOLANG_VERSION}-alpine AS builder
+FROM golang:${GOLANG_TAG} AS builder
 
 ARG ATLANTIS_VERSION=dev
 ENV ATLANTIS_VERSION=${ATLANTIS_VERSION}