Change UseVPC to DdUseVPC in PrivateLink documentation (#732)

Co-authored-by: Stephan Telling <[email protected]>

aws/logs_monitoring/README.md

@@ -287,7 +287,7 @@ You can run the Forwarder in a VPC private subnet and send data to Datadog over
 1. Follow [these instructions][14] to add the Datadog `api`, `http-logs.intake`, and `trace.agent` endpoints to your VPC.
 2. Follow the [instructions][15] to add the AWS Secrets Manager and S3 endpoints to your VPC.
 3. When installing the Forwarder with the CloudFormation template:
-   1. Set `UseVPC` to `true`.
+   1. Set `DdUseVPC` to `true`.
    2. Set `VPCSecurityGroupIds` and `VPCSubnetIds` based on your VPC settings.
    3. Set `DdFetchLambdaTags` to `false`, because AWS Resource Groups Tagging API doesn't support PrivateLink.