Updated key name

Author: wiazur

Search/BingCustomSearch/README.md

@@ -27,7 +27,7 @@ To get these samples running locally, simply get the pre-requisites above, then:
 
 1. git clone https://github.com/Azure-Samples/cognitive-services-java-sdk-samples.git
 2. cd cognitive-services-java-sdk-samples/Search/BingCustomSearch
-3. Either set a system environment variable named `AZURE_BING_SAMPLES_API_KEY` to your cognitive Services API key, or copy your key into the program. If you are going to set the AZURE_BING_SAMPLES_API_KEY environment variable, make sure to set it based on your OS, then reopen your command prompt or IDE. If not, you might get an API key not found exception.
+3. set a system environment variable named `BING_CUSTOM_SEARCH_SUBSCRIPTION_KEY` with your subscription key as a value, then reopen your command prompt or IDE. If not, you might get an API key not found exception.
 4. Set env variable AZURE_BING_SAMPLES_CUSTOM_CONFIG_ID to your custom configuration id. Can set to 1 if you do not have a custom config id.
 5. mvn compile exec:java
 
@@ -41,4 +41,4 @@ If you don't have a Microsoft Azure subscription you can get a FREE trial accoun
 
 ---
 
-This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact [[email protected]](mailto:[email protected]) with any additional questions or comments.
+This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact [[email protected]](mailto:[email protected]) with any additional questions or comments.