Fix erroneous lookup in github webhook handler.

While adding tests I erroneously changed a lookup in a package event
json from ".package.package_version.container_metadata.tag.name" to
".package.package_version.tag_name", which turned out to be both (a)
the wrong thing to do and (b) causing an internal server error because
"tag_name" field is not available (anymore?) for package events.

internal/controlplane/handlers_githubwebhooks.go

@@ -712,13 +712,7 @@ func extractArtifactVersionFromPayload(ctx context.Context, payload map[string]a
 	if err != nil {
 		return nil, err
 	}
-	// Previous lookup was done at this path
-	// ".package.package_version.container_metadata.tag.name",
-	// which is unfortunately not have available under go-github,
-	// as field "container_metadata" is missing form its structs.
-	// I suggest using the following, although it's still to be
-	// verified whether that's the right one.
-	tag, err := util.JQReadFrom[string](ctx, ".package.package_version.tag_name", payload)
+	tag, err := util.JQReadFrom[string](ctx, ".package.package_version.container_metadata.tag.name", payload)
 	if err != nil {
 		return nil, err
 	}

internal/controlplane/handlers_githubwebhooks_test.go

@@ -507,16 +507,21 @@ func (s *UnitTestSuite) TestHandlGitHubWebHook() {
 			// https://docs.github.com/en/webhooks/webhook-events-and-payloads#package
 			event: "package",
 			// https://pkg.go.dev/github.com/google/go-github/[email protected]/github#PackageEvent
-			payload: &github.PackageEvent{
+			payload: &packageEvent{
 				Action: github.String("published"),
-				Package: &github.Package{
+				Package: &pkg{
 					Name:        github.String("package-name"),
 					PackageType: github.String("package-type"),
 					// .package.package_version.container_metadata.tag.name
-					PackageVersion: &github.PackageVersion{
+					PackageVersion: &packageVersion{
 						ID:      github.Int64(1),
 						Version: github.String("version"),
-						TagName: github.String("tagname"),
+						ContainerMedatata: &containerMetadata{
+							Tag: &tag{
+								Digest: github.String("digest"),
+								Name:   github.String("tag"),
+							},
+						},
 					},
 					Owner: &github.User{
 						Login: github.String("login"),
@@ -540,15 +545,21 @@ func (s *UnitTestSuite) TestHandlGitHubWebHook() {
 			// https://docs.github.com/en/webhooks/webhook-events-and-payloads#package
 			event: "package",
 			// https://pkg.go.dev/github.com/google/go-github/[email protected]/github#PackageEvent
-			payload: &github.PackageEvent{
+			payload: &packageEvent{
 				Action: github.String("updated"),
-				Package: &github.Package{
+				Package: &pkg{
 					Name:        github.String("package-name"),
 					PackageType: github.String("package-type"),
-					PackageVersion: &github.PackageVersion{
+					// .package.package_version.container_metadata.tag.name
+					PackageVersion: &packageVersion{
 						ID:      github.Int64(1),
 						Version: github.String("version"),
-						TagName: github.String("tagname"),
+						ContainerMedatata: &containerMetadata{
+							Tag: &tag{
+								Digest: github.String("digest"),
+								Name:   github.String("tag"),
+							},
+						},
 					},
 					Owner: &github.User{
 						Login: github.String("login"),
@@ -1955,6 +1966,35 @@ type garbage struct {
 	Garbage *string `json:"garbage,omitempty"`
 }
 
+type packageEvent struct {
+	Action  *string              `json:"action,omitempty"`
+	Repo    *github.Repository   `json:"repository,omitempty"`
+	Org     *github.Organization `json:"org,omitempty"`
+	Package *pkg                 `json:"package,omitempty"`
+}
+
+type pkg struct {
+	Name           *string         `json:"name,omitempty"`
+	PackageType    *string         `json:"package_type,omitempty"`
+	PackageVersion *packageVersion `json:"package_version,omitempty"`
+	Owner          *github.User    `json:"owner,omitempty"`
+}
+
+type packageVersion struct {
+	ID                *int64             `json:"id,omitempty"`
+	Version           *string            `json:"version,omitempty"`
+	ContainerMedatata *containerMetadata `json:"container_metadata,omitempty"`
+}
+
+type containerMetadata struct {
+	Tag *tag `json:"tag,omitempty"`
+}
+
+type tag struct {
+	Digest *string `json:"digest,omitempty"`
+	Name   *string `json:"name,omitempty"`
+}
+
 type branchProtectionConfigurationEvent struct {
 	Action *string              `json:"action,omitempty"`
 	Repo   *github.Repository   `json:"repo,omitempty"`