Docs: [AEA-3942] - add repeat number to psu api spec (#104)

## Summary


- Routine Change


Adds the number of repeats allowed for a eRD

packages/specification/examples/request-erd-dispatched.json

@@ -0,0 +1,63 @@
+{
+    "resourceType": "Bundle",
+    "type": "transaction",
+    "entry": [
+      {
+        "fullUrl": "http://example.org/fhir/Task/4d70678c-81e4-4ff4-8c67-17596fd0aa46",
+        "resource": {
+          "resourceType": "Task",
+          "id": "4d70678c-81e4-4ff4-8c67-17596fd0aa46",
+          "basedOn": [
+            {
+              "identifier": {
+                "system": "https://fhir.nhs.uk/Id/prescription-order-number",
+                "value": "07A66F-A83008-1EEEA0"
+              }
+            }
+          ],
+          "status": "completed",
+          "businessStatus": {
+            "coding": [
+              {
+                "system": "https://fhir.nhs.uk/CodeSystem/task-businessStatus-nppt",
+                "code": "Dispatched"
+              }
+            ]
+          },
+          "intent": "order",
+          "focus": {
+            "identifier": {
+              "system": "https://fhir.nhs.uk/Id/prescription-order-item-number",
+              "value": "6989b7bd-8db6-428c-a593-4022e3044c00"
+            }
+          },
+          "for": {
+            "identifier": {
+              "system": "https://fhir.nhs.uk/Id/nhs-number",
+              "value": "9449304130"
+            }
+          },
+          "lastModified": "2024-01-30T12:01:24Z",
+          "owner": {
+            "identifier": {
+              "system": "https://fhir.nhs.uk/Id/ods-organization-code",
+              "value": "C9Z1O"
+            }
+          },
+          "input": [
+            {
+              "type": {
+                "text": "Repeat Number"
+              },
+              "valueInteger": 2
+            }
+          ]
+        },
+        "request": {
+          "method": "POST",
+          "url": "Task"
+        }
+      }
+    ]
+  }
+

packages/specification/schemas/resources/UpdatePrescriptionStatusTask.yaml

@@ -1,5 +1,5 @@
 type: object
-required: [id, resourceType, basedOn, status, businessStatus, intent, focus, for, lastModified, owner]
+required: [id, resourceType, basedOn, status, businessStatus, intent, focus, for, lastModified, owner, input]
 properties:
   resourceType:
     type: string
@@ -107,3 +107,21 @@ properties:
           value:
             type: string
             example: C9Z1O
+  input:
+    type: array
+    description: The eRD Repeat Number, with the prescription tracking status updates for eRD prescriptions. This is optional and only required for eRD type prescriptions.
+    items:
+      type: object
+      required: [_type, valueInteger]
+      properties:
+        _type: 
+          type: object
+          required: [text]
+          properties:
+            text:
+              type: string
+              enum: [Repeat Number]
+        valueInteger:
+          type: integer
+          minimum: 1
+          maximum: 6