Bump to go 1.23 and run 'go mod tidy'

Author: thockin

v2/Makefile

@@ -11,4 +11,4 @@ test:
 verify:
 	GODEBUG=gotypesalias=0 ./hack/verify-examples.sh
 	GODEBUG=gotypesalias=1 ./hack/verify-examples.sh
-	./hack/verify-go-directive.sh 1.20
+	./hack/verify-go-directive.sh 1.23

v2/go.mod

@@ -1,15 +1,15 @@
 module k8s.io/gengo/v2
 
-go 1.20
+go 1.23
 
 require (
+	github.com/google/go-cmp v0.6.0
 	github.com/spf13/pflag v1.0.5
 	golang.org/x/tools v0.16.1
 	k8s.io/klog/v2 v2.2.0
 )
 
 require (
 	github.com/go-logr/logr v0.2.0 // indirect
-	github.com/google/go-cmp v0.6.0 // indirect
 	golang.org/x/mod v0.14.0 // indirect
 )

v2/go.sum

@@ -7,6 +7,7 @@ github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An
 golang.org/x/mod v0.14.0 h1:dGoOF9QVLYng8IHTm7BAyWqCqSheQ5pYWGhzW00YJr0=
 golang.org/x/mod v0.14.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
+golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/tools v0.16.1 h1:TLyB3WofjdOEepBHAU20JdNC1Zbg87elYofWYAY5oZA=
 golang.org/x/tools v0.16.1/go.mod h1:kYVVN6I1mBNoB1OX+noeBjbRk4IUEPa7JJ+TJMEooJ0=
 k8s.io/klog/v2 v2.2.0 h1:XRvcwJozkgZ1UQJmfMGpvRthQHOvihEhYtDfAaxMz/A=