use more specific version tag

Author: mrtnsch

packages/modules/azurecosmosdb/src/azure-cosmosdb-emulator-container.ts

@@ -23,7 +23,7 @@ export class AzureCosmosDbEmulatorContainer extends GenericContainer {
   private explorerEnabled = DEFAULT_EXPLORER_ENABLED;
   private portGenerator: PortGenerator;
 
-  constructor(image = "mcr.microsoft.com/cosmosdb/linux/azure-cosmos-emulator:vnext-preview") {
+  constructor(image = "mcr.microsoft.com/cosmosdb/linux/azure-cosmos-emulator:vnext-EN20250228") {
     super(image);
     this.portGenerator = new RandomUniquePortGenerator();
     this.withWaitStrategy(Wait.forLogMessage(COSMOS_READY_LOG_MESSAGE));