header names must be lowercase: Metadata

[yvespp]

The SDK sets the header "Metadata" in different places (search case sensitive for insert_header("Metadata") which the the validation here doesn't like:

azure-sdk-for-rust/sdk/core/src/headers/mod.rs

Line 191 in fd5de99

"header names must be lowercase: {c}"

All the code that sets the header is generated by AutoRust, e.g.

azure-sdk-for-rust/services/svc/imds/src/package_2021_02_01/operations.rs

Line 122 in fd5de99

req.insert_header("Metadata", &this.metadata);

Change the validation or the header?
Why isn't this caught by a test?

[bmc-msft]

@yvespp the generated crates do not yet have integration tests.