Update Key Vault EC Key SECP256K1 curve name to P-256K
Currently there exists a breaking discrepancy between Azure Portal and Azure CLI.
When you create an EC Key via the Portal, the curve name in question is labelled as SECP256K1, and expects the signing algorithm to be ECDSA256.
This is the legacy naming convention (keyvault-preview). See https://docs.microsoft.com/en-us/cli/azure/ext/keyvault-preview/keyvault/key?view=azure-cli-latest#ext-keyvault-preview-az-keyvault-key-create
When you create the same type of key via Azure CLI, the curve name is P-256K and expects the signing algorithm to be ES256. This is the "release" naming convention. See https://docs.microsoft.com/en-us/cli/azure/keyvault/key?view=azure-cli-latest#az-keyvault-key-create
Functionally, these keys are identical. But the discrepancy in the naming convention makes it difficult for a project to support keys created both via Azure CLI as well as via the Azure Portal.