[release-1.9] 🌱 Bump to Go 1.21

.github/workflows/cover.yaml

@@ -20,7 +20,7 @@ jobs:
     - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
     - uses: actions/setup-go@0c52d547c9bc32b1aa3301fd7a9cb496313a4491 # v5.0.0
       with:
-        go-version: '1.20'
+        go-version: '1.21'
     - run: "PATH=/usr/local/go/bin:$PATH make test-cover"
     - uses: Wandalen/wretry.action@a163f62ae554a8f3cbe27b23db15b60c0ae2e93c # v1.3.0 Retry codecov upload. It is flaky due to a known issue https://community.codecov.com/t/upload-issues-unable-to-locate-build-via-github-actions-api/3954
       with:

.golangci.yml

@@ -1,6 +1,6 @@
 run:
   timeout: 10m
-  go: "1.20"
+  go: "1.21"
   skip-files:
     - "zz_generated.*\\.go$"
   allow-parallel-runners: true

Makefile

@@ -23,7 +23,7 @@ SHELL:=/usr/bin/env bash
 #
 # Go.
 #
-GO_VERSION ?= 1.20.12
+GO_VERSION ?= 1.21.5
 GO_CONTAINER_IMAGE ?= docker.io/library/golang:$(GO_VERSION)
 
 # Use GOPROXY environment variable if set

hack/ensure-go.sh

@@ -21,7 +21,7 @@ set -o pipefail
 # MIN_GO_VERSION is the minimum, supported Go version.
 # Note: Enforce only the minor version as we can't guarantee that
 # the images we use in ProwJobs already use the latest patch version.
-MIN_GO_VERSION="go${MIN_GO_VERSION:-1.20}"
+MIN_GO_VERSION="go${MIN_GO_VERSION:-1.21}"
 
 # Ensure the go tool exists and is a viable version.
 verify_go_version() {