Bump golang to 1.20.4

Since I was bumping the version I decided to move it to
Makefile.variables because it's used in more than one place.

Signed-off-by: Juan-Luis de Sousa-Valadas Castaño <[email protected]>

Dockerfile

@@ -1,8 +1,10 @@
 # Build the manager binary
-FROM golang:1.20 as builder
+ARG BUILD_IMG
 ARG TARGETOS
 ARG TARGETARCH
 
+FROM ${BUILD_IMG} as builder
+
 WORKDIR /workspace
 # Copy the Go Modules manifests
 COPY go.mod go.mod

Makefile

@@ -96,7 +96,10 @@ run: manifests generate fmt vet ## Run a controller from your host.
 # More info: https://docs.docker.com/develop/develop-images/build_enhancements/
 .PHONY: docker-build
 docker-build: test ## Build docker image with the manager.
-	docker build -t ${IMG} .
+	docker build \
+	  -t ${IMG} \
+	  --build-arg BUILD_IMG=golang:$(GO_VERSION) \
+	.
 
 k0smotron-image-bundle.tar: docker-build
 	docker save ${IMG} -o k0smotron-image-bundle.tar
@@ -195,10 +198,11 @@ clean:
 	  k0smotron-image-bundle.tar \
 	  $(LOCALBIN)
 
-hack/lint/.golangci-lint.stamp: hack/lint/Dockerfile
+hack/lint/.golangci-lint.stamp: hack/lint/Dockerfile Makefile.variables
 	docker build \
 	  -t k0smotron.golangci-lint \
-	  --build-arg GOLANGCILINT_VERSION=1.52.2 \
+	  --build-arg BUILD_IMG=golang:$(GO_VERSION) \
+	  --build-arg GOLANGCILINT_VERSION=$(GOLANGCILINT_VERSION) \
 	  -f hack/lint/Dockerfile \
 	  .
 	touch -- '$@'

Makefile.variables

@@ -1,2 +1,4 @@
 KUSTOMIZE_VERSION ?= v5.0.1
 CONTROLLER_TOOLS_VERSION ?= v0.11.4
+GO_VERSION ?= 1.20.4
+GOLANGCILINT_VERSION ?= 1.52.2

hack/lint/Dockerfile

@@ -1,5 +1,6 @@
-FROM golang:1.20 as builder
+ARG BUILD_IMG
 
+FROM ${BUILD_IMG} as builder
 ARG GOLANGCILINT_VERSION
 
-RUN go install github.com/golangci/golangci-lint/cmd/golangci-lint@v${GOLANGCILINT_VERSION}
+RUN go install github.com/golangci/golangci-lint/cmd/golangci-lint@v${GOLANGCILINT_VERSION}