Add support for Slack as a notification channel type

Signed-off-by: bcmmbaga <bethuelmbaga12@gmail.com>

shared/management/http/api/openapi.yml

@@ -4751,6 +4751,7 @@ components:
       enum:
         - email
         - webhook
+        - slack
       example: "email"
     NotificationEventType:
       type: string
@@ -4804,6 +4805,7 @@ components:
             Channel-specific target configuration. The shape depends on the `type` field:
             - `email`: requires an `EmailTarget` object
             - `webhook`: requires a `WebhookTarget` object
+            - `slack`: requires a `WebhookTarget` object
           oneOf:
             - $ref: '#/components/schemas/EmailTarget'
             - $ref: '#/components/schemas/WebhookTarget'
@@ -4837,6 +4839,7 @@ components:
             Channel-specific target configuration. The shape depends on the `type` field:
             - `email`: an `EmailTarget` object
             - `webhook`: a `WebhookTarget` object
+            - `slack`: a `WebhookTarget` object
           oneOf:
             - $ref: '#/components/schemas/EmailTarget'
             - $ref: '#/components/schemas/WebhookTarget'

shared/management/http/api/types.gen.go

@@ -686,6 +686,7 @@ func (e NetworkResourceType) Valid() bool {
 // Defines values for NotificationChannelType.
 const (
 	NotificationChannelTypeEmail   NotificationChannelType = "email"
+	NotificationChannelTypeSlack   NotificationChannelType = "slack"
 	NotificationChannelTypeWebhook NotificationChannelType = "webhook"
 )
 
@@ -694,6 +695,8 @@ func (e NotificationChannelType) Valid() bool {
 	switch e {
 	case NotificationChannelTypeEmail:
 		return true
+	case NotificationChannelTypeSlack:
+		return true
 	case NotificationChannelTypeWebhook:
 		return true
 	default: