Create Ingress2gateway version annotation and attach it to Gateway.

* Ingress2gateway annotation will track the current version of the
  ingress2gateway tool. The version is currently a string that needs to
  be updated manually before release.
* This annotation will be attached to the resulting Gateway during print
  since this is an output-only translation, and we can avoid interfering
  with existing Gateway translation tests.

RELEASE.md

@@ -23,6 +23,9 @@ a PR. This must go through the regular PR review process and get merged into the
 `main` branch. Approval of the PR indicates community consensus for a new
 release.
 
+### Update ingress2gateway version in annotation
+1. Once the new release version is determined, update `CurrentVersion` in [pkg/i2gw/ingress2gateway.go](pkg/i2gw/ingress2gateway.go) so the translated Gateways will reflect the correct ingress2gateway tool version that generated them.
+
 ### Patch a release
 
 1. Create a new branch in your fork named something like `<githubuser>/release-x.x.x`. Use the new branch

cmd/print.go

@@ -117,6 +117,10 @@ func (pr *PrintRunner) outputResult(gatewayResources []i2gw.GatewayResources) {
 		resourceCount += len(r.Gateways)
 		for _, gateway := range r.Gateways {
 			gateway := gateway
+			if gateway.Annotations == nil {
+				gateway.Annotations = make(map[string]string)
+			}
+			gateway.Annotations[i2gw.GeneratorAnnotationKey] = fmt.Sprintf("ingress2gateway-%s", i2gw.CurrentVersion)
 			err := pr.resourcePrinter.PrintObj(&gateway, os.Stdout)
 			if err != nil {
 				fmt.Printf("# Error printing %s Gateway: %v\n", gateway.Name, err)

pkg/i2gw/ingress2gateway.go

@@ -31,6 +31,10 @@ import (
 	gatewayv1beta1 "sigs.k8s.io/gateway-api/apis/v1beta1"
 )
 
+const GeneratorAnnotationKey = "gateway.networking.k8s.io/generator"
+
+var CurrentVersion = "0.3.0"
+
 func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile string, providers []string, providerSpecificFlags map[string]map[string]string) ([]GatewayResources, map[string]string, error) {
 	var clusterClient client.Client