Delete changelog.md
Delete changelog.md

We use the GitHub release functionality now. Check out https://github.com/Azure/azure-event-hubs-java/releases for the changelog.
navalev/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,navalev/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,SreeramGarlapati/azure-event-hubs-java,Azure/azure-sdk-for-java,navalev/azure-sdk-for-java,navalev/azure-sdk-for-java,navalev/azure-sdk-for-java,selvasingh/azure-sdk-for-java,selvasingh/azure-sdk-for-java,selvasingh/azure-sdk-for-java