[azure-security-attestation-cpp] Use non-deprecated syntax

[antkmsft]

Updating a single line in the released SDK to a syntax that works with both old and new azure-core-cpp versions. The old syntax will be deprecated in the upcoming azure-core-cpp release, which, if not fixed, will result in deprecation warnings (potentially treated as errors) for the existing azure-security-attestation-cpp customers.

[BillyONeal]

Has this been submitted upstream?

[antkmsft]

@BillyONeal, I have updated the PR so that it matches the line numbers exactly, so it is easier to verify visually.

Thank you for checking - yes, this change is in azure-sdk-for-cpp repo, see the latest main - https://github.com/Azure/azure-sdk-for-cpp/blob/main/sdk/attestation/azure-security-attestation/inc/azure/attestation/attestation_client.hpp#L187

The line numbers have changed since then, but here would be this line in the azure-security-attestation_1.1.0 release - https://github.com/Azure/azure-sdk-for-cpp/blob/azure-security-attestation_1.1.0/sdk/attestation/azure-security-attestation/inc/azure/attestation/attestation_client.hpp#L176-L179 (GetOpenIdMetadata() function). And if you look around, {} for the context parameter is used in other functions in the same file.

We just feel, this change is not sufficient to make another release of azure-security-attestation, so we just patch it. In the upcoming azure-core-cpp release, Context::ApplicationContext is deprecated: https://github.com/Azure/azure-sdk-for-cpp/blob/main/sdk/core/azure-core/inc/azure/core/context.hpp#L379-L381

We also have the same change made for our vcpkg registry which we use for beta releases, https://github.com/Azure/azure-sdk-vcpkg-betas

[BillyONeal]

Thanks!