add collaborator search contract

contracts/v1/collaborator-search-response.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "type": "array",
+  "items": {
+    "type": "object",
+    "additionalProperties": false,
+    "required": ["id", "login", "display_name"],
+    "properties": {
+      "id": { "type": "string" },
+      "login": { "type": "string" },
+      "display_name": { "type": "string" }
+    }
+  }
+}

fixtures/v1/collaborator-search.response.json

@@ -0,0 +1,7 @@
+[
+  {
+    "id": "123456",
+    "login": "example_streamer",
+    "display_name": "ExampleStreamer"
+  }
+]