Update dependency immutable to v5

Author: renovate[bot]

src/servicebroker-npm/package.json

@@ -28,7 +28,7 @@
 		"await-semaphore": "^0.1.3",
 		"cancellationtoken": "^2.2.0",
 		"caught": "^0.1.3",
-		"immutable": "^4.3.1",
+		"immutable": "^5.0.0",
 		"msgpack-lite": "^0.1.26",
 		"nerdbank-streams": "^2.11.79",
 		"strict-event-emitter-types": "^2.0.0",