Add .prettierrc.yml (#4817)
Add .prettierrc.yml (#4817)

- Part of Azure/azure-sdk#225

xingwu1/azure-sdk-for-node,xingwu1/azure-sdk-for-node,Azure/azure-sdk-for-node,Azure/azure-sdk-for-node,Azure/azure-sdk-for-node,xingwu1/azure-sdk-for-node