feat(go): upgrade 1.20.7 -> 1.20.9

Includes comment warnings about inconsistent v1.21.X functionality

.github/workflows/ci.yml

@@ -15,9 +15,12 @@ on:
     - prep-v[1-9].*
 
 env:
-  BUILDTIME_BASE: "golang:1.20.7-alpine3.18"
+  # Upgrading to Go 1.21.{0,1,2} seems to in cause some sort of race condition that causes tests to fail sporadically.
+  # Sometimes they fail in apparent race conditions, other times they end up with nil pointer and SIGSEGV errors. We'll
+  # either need to try with a future bug fix release or do some in-depth debugging before we upgrade.
+  BUILDTIME_BASE: "golang:1.20.9-alpine3.18"
   RUNTIME_BASE: "alpine:3.18"
-  GO_VERSION: "~1.20.7"
+  GO_VERSION: "~1.20.9"
   GO_CACHE: "/home/runner/.cache/go-build"
   GO_MOD_CACHE: "/home/runner/go/pkg/mod"
 

Makefile

@@ -17,7 +17,10 @@ DOCKER=$(if $(or $(IN_DOCKER_GROUP),$(IS_ROOT),$(OSX)),docker,sudo docker)
 MAKEFILE_DIR=$(dir $(realpath $(firstword $(MAKEFILE_LIST))))
 UPSTREAM_IMPORT_PATH=$(GOPATH)/src/github.com/cloudnativelabs/kube-router/
 BUILD_IN_DOCKER?=true
-DOCKER_BUILD_IMAGE?=golang:1.20.7-alpine3.18
+# Upgrading to Go 1.21.{0,1,2} seems to in cause some sort of race condition that causes tests to fail sporadically.
+# Sometimes they fail in apparent race conditions, other times they end up with nil pointer and SIGSEGV errors. We'll
+# either need to try with a future bug fix release or do some in-depth debugging before we upgrade.
+DOCKER_BUILD_IMAGE?=golang:1.20.9-alpine3.18
 ## These variables are used by the Dockerfile as the bases for building and creating the runtime container
 ## During CI these come from .github/workflows/ci.yaml below we define for local builds as well
 GO_CACHE?=$(shell go env GOCACHE)