Added getblockhash call

doc/openapi/v0/cyphernode-api.yaml

@@ -436,6 +436,38 @@ paths:
               schema:
                 $ref: '#/components/schemas/ApiResponseTemporarilyUnavailable'
 
+  /getblockhash:
+    get:
+      tags:
+        - "block"
+        - "core features"
+      summary: "Get block hash matching height provided."
+      description: "Returns the block matching the height provided of the watching Bitcoin node."
+      operationId: "getBlockHash"
+      responses:
+        '200':
+          description: "successful operation"
+          content:
+            application/json:
+              schema:
+                type: "object"
+                required:
+                  - "result"
+                properties:
+                  result:
+                    $ref: '#/components/schemas/TypeHashString'
+                  error:
+                    type: "string"
+                  id:
+                    type: "string"
+        '403':
+          $ref: '#/components/schemas/ApiResponseNotAllowed'
+        '503':
+          description: "Resource temporarily unavailable"
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ApiResponseTemporarilyUnavailable'
   /getbestblockhash:
     get:
       tags: