Support manifest services without name

Both manifest service formats are now supported:

```
services:
  - my_service
  - name: your_service
```

Co-authored-by: Danail Branekov <danailster@gmail.com>

api/payloads/manifest.go

@@ -2,12 +2,14 @@ package payloads
 
 import (
 	"errors"
+	"fmt"
 	"regexp"
 
 	"code.cloudfoundry.org/korifi/api/repositories"
 	korifiv1alpha1 "code.cloudfoundry.org/korifi/controllers/api/v1alpha1"
 	"code.cloudfoundry.org/korifi/tools"
 	"github.com/jellydator/validation"
+	"gopkg.in/yaml.v3"
 
 	"code.cloudfoundry.org/bytefmt"
 )
@@ -70,6 +72,21 @@ type ManifestApplicationService struct {
 	BindingName *string `json:"binding_name" yaml:"binding_name"`
 }
 
+func (s *ManifestApplicationService) UnmarshalYAML(value *yaml.Node) error {
+	if value.Kind == yaml.ScalarNode && value.Tag == "!!str" {
+		s.Name = value.Value
+		return nil
+	}
+
+	type manifestApplicationService ManifestApplicationService
+	err := value.Decode((*manifestApplicationService)(s))
+	if err != nil {
+		return fmt.Errorf("invalid service: line %d, column %d: %w", value.Line, value.Column, err)
+	}
+
+	return nil
+}
+
 type ManifestRoute struct {
 	Route *string `json:"route" yaml:"route"`
 }

api/payloads/manifest_test.go

@@ -8,6 +8,7 @@ import (
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
+	"gopkg.in/yaml.v3"
 )
 
 var _ = Describe("Manifest payload", func() {
@@ -739,33 +740,82 @@ var _ = Describe("Manifest payload", func() {
 		})
 	})
 
-	Describe("ManifestApplicationServices", func() {
-		var (
-			validateErr          error
-			testManifestServices ManifestApplicationService
-		)
+	Describe("ManifestApplicationService", func() {
+		Describe("Unmarshall", func() {
+			var (
+				unmarshalErr        error
+				serviceString       string
+				unmarshalledService ManifestApplicationService
+			)
 
-		BeforeEach(func() {
-			testManifestServices = ManifestApplicationService{
-				Name: "my-service",
-			}
-		})
+			BeforeEach(func() {
+				serviceString = "name: my-svc"
+				unmarshalledService = ManifestApplicationService{}
+			})
 
-		JustBeforeEach(func() {
-			validateErr = validator.DecodeAndValidateYAMLPayload(createYAMLRequest(testManifestServices), &ManifestApplicationService{})
-		})
+			JustBeforeEach(func() {
+				unmarshalErr = yaml.Unmarshal([]byte(serviceString), &unmarshalledService)
+			})
 
-		It("validates the struct", func() {
-			Expect(validateErr).NotTo(HaveOccurred())
+			It("succeeds", func() {
+				Expect(unmarshalErr).NotTo(HaveOccurred())
+				Expect(unmarshalledService).To(Equal(ManifestApplicationService{
+					Name: "my-svc",
+				}))
+			})
+
+			When("the name tag is missing", func() {
+				BeforeEach(func() {
+					serviceString = "my-svc"
+				})
+
+				It("succeeds", func() {
+					Expect(unmarshalErr).NotTo(HaveOccurred())
+					Expect(unmarshalledService).To(Equal(ManifestApplicationService{
+						Name: "my-svc",
+					}))
+				})
+
+				When("the value is not a string", func() {
+					BeforeEach(func() {
+						serviceString = "123"
+					})
+
+					It("errors", func() {
+						Expect(unmarshalErr).To(MatchError(ContainSubstring("invalid service")))
+					})
+				})
+			})
 		})
 
-		When("name is not specified", func() {
+		Describe("Validate", func() {
+			var (
+				validateErr          error
+				testManifestServices ManifestApplicationService
+			)
+
 			BeforeEach(func() {
-				testManifestServices.Name = ""
+				testManifestServices = ManifestApplicationService{
+					Name: "my-service",
+				}
 			})
 
-			It("returns a validation error", func() {
-				expectUnprocessableEntityError(validateErr, "name cannot be blank")
+			JustBeforeEach(func() {
+				validateErr = validator.DecodeAndValidateYAMLPayload(createYAMLRequest(testManifestServices), &ManifestApplicationService{})
+			})
+
+			It("validates the struct", func() {
+				Expect(validateErr).NotTo(HaveOccurred())
+			})
+
+			When("name is not specified", func() {
+				BeforeEach(func() {
+					testManifestServices.Name = ""
+				})
+
+				It("returns a validation error", func() {
+					expectUnprocessableEntityError(validateErr, "name cannot be blank")
+				})
 			})
 		})
 	})