Fix CI for 1.16

Run `go mod tidy` before building image so the go.mod has
the required deps.

See https://blog.golang.org/go116-module-changes#TOC_3.

.github/workflows/apidiff.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v2
         with:
-          go-version: '1.15'
+          go-version: '1.16'
       - name: Execute go-apidiff
         uses: joelanford/go-apidiff@v0.1.0
         with:

CONTRIBUTING.md

@@ -10,7 +10,7 @@ Please see https://git.k8s.io/community/CLA.md for more info.
 
 ## Prerequisites
 
-- [go](https://golang.org/dl/) version v1.15+.
+- [go](https://golang.org/dl/) version v1.16+.
 - [docker](https://docs.docker.com/install/) version 17.03+.
 - [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) version v1.11.3+.
 - [kustomize](https://sigs.k8s.io/kustomize/docs/INSTALL.md) v3.1.0+

pkg/cli/alpha/config-gen/cmd.go

@@ -24,6 +24,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	// TODO: switch to embed
 	"github.com/markbates/pkger"
 	"github.com/spf13/cobra"
 

test/e2e/utils/test_context.go

@@ -220,6 +220,14 @@ func (t *TestContext) Make(makeOptions ...string) error {
 	return err
 }
 
+// Tidy runs `go mod tidy` so that go 1.16 build doesn't fail.
+// See https://blog.golang.org/go116-module-changes#TOC_3.
+func (t *TestContext) Tidy() error {
+	cmd := exec.Command("go", "mod", "tidy")
+	_, err := t.Run(cmd)
+	return err
+}
+
 // Destroy is for cleaning up the docker images for testing
 func (t *TestContext) Destroy() {
 	//nolint:gosec

test/e2e/v3/plugin_cluster_test.go

@@ -117,6 +117,10 @@ func Run(kbc *utils.TestContext) {
 	var controllerPodName string
 	var err error
 
+	By("updating the go.mod")
+	err = kbc.Tidy()
+	ExpectWithOffset(1, err).NotTo(HaveOccurred())
+
 	By("building the controller image")
 	err = kbc.Make("docker-build", "IMG="+kbc.ImageName)
 	ExpectWithOffset(1, err).NotTo(HaveOccurred())