Bug 30674: x-koha-override should use collectionFormat: csv

This patch makes this header parameter rely on the OpenAPI spec to
validate and document the available options.

Right now the only place is in POST and PUT /holds.

To test:
1. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/holds.t \
           t/db_dependent/api/v1/auth_authenticate_api_request.t
=> SUCCESS: Tests pass
2. Apply this patch
3. Repeat 1
=> SUCCESS: Tests still pass!
4. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

api/v1/swagger/paths/holds.yaml

@@ -180,10 +180,15 @@
             - pickup_library_id
           additionalProperties: false
       - name: x-koha-override
-        description: "Comma-separated list of overrides (valid values: any)"
         in: header
-        type: string
         required: false
+        description: Overrides list sent as a request header
+        type: array
+        items:
+          type: string
+          enum:
+            - any
+        collectionFormat: csv
     consumes:
       - application/json
     produces:
@@ -561,10 +566,15 @@
     summary: Get valid pickup locations for hold
     parameters:
       - name: x-koha-override
-        description: "Comma-separated list of overrides (valid values: any)"
         in: header
-        type: string
         required: false
+        description: Overrides list sent as a request header
+        type: array
+        items:
+          type: string
+          enum:
+            - any
+        collectionFormat: csv
       - $ref: "../swagger.yaml#/parameters/hold_id_pp"
       - $ref: "../swagger.yaml#/parameters/match"
       - $ref: "../swagger.yaml#/parameters/order_by"