APPS-5889: add docs for liveness_health_check (digitalocean#1024)

* adding openapi changes.

* remove default, fix lint

* fix ref

* add missing example

---------

Co-authored-by: danaelhe <42972711+danaelhe@users.noreply.github.com>

Author: ssaengs

specification/resources/apps/models/app_health_check_spec.yml

@@ -0,0 +1,54 @@
+type: object
+properties:
+  failure_threshold:
+    type: integer
+    format: int32
+    description: The number of failed health checks before considered unhealthy.
+    minimum: 1
+    maximum: 50
+    example: 18
+
+  port:
+    type: integer
+    format: int64
+    description: The port on which the health check will be performed.
+    example: 80
+    maximum: 65535
+    minimum: 1
+
+  http_path:
+    type: string
+    description: The route path used for the HTTP health check ping. If not set, the HTTP health check will be disabled and a TCP health check used instead.
+    example: /health
+
+  initial_delay_seconds:
+    type: integer
+    format: int32
+    description: The number of seconds to wait before beginning health checks.
+    minimum: 0
+    maximum: 3600
+    example: 30
+
+  period_seconds:
+    type: integer
+    format: int32
+    description: The number of seconds to wait between health checks.
+    minimum: 1
+    maximum: 300
+    example: 10
+
+  success_threshold:
+    type: integer
+    format: int32
+    description: The number of successful health checks before considered healthy.
+    example: 1
+    minimum: 1
+    maximum: 1
+
+  timeout_seconds:
+    type: integer
+    format: int32
+    description: The number of seconds after which the check times out.
+    minimum: 1
+    maximum: 120
+    example: 1

specification/resources/apps/models/app_service_spec.yml

@@ -13,6 +13,9 @@ allOf:
     health_check:
       $ref: app_service_spec_health_check.yml
 
+    liveness_health_check:
+      $ref: app_health_check_spec.yml
+
     protocol:
       type: string
       description: |

specification/resources/apps/models/app_worker_spec.yml

@@ -5,6 +5,8 @@ allOf:
   properties:
     termination:
       $ref: app_worker_spec_termination.yml
+    liveness_health_check:
+      $ref: app_health_check_spec.yml
 required:
   - name