Update contributing guidelines to include link to unit testing (#7856)
Update contributing guidelines to include link to unit testing (#7856)


Azure/azure-sdk-for-java,selvasingh/azure-sdk-for-java,Azure/azure-sdk-for-java,selvasingh/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,selvasingh/azure-sdk-for-java,Azure/azure-sdk-for-java