chore(deps): prepare release 0.6.0

- vendor unpublished tdx-attest-rs and tdx-attest-sys crates
  to be able to publish to crates.io
- Updated package versions in `Cargo.toml` and `Cargo.lock` to 0.6.0.

Signed-off-by: Harald Hoyer <harald@matterlabs.dev>

crates/teepot-tee-quote-verification-rs/src/empty.rs

@@ -1,4 +1,3 @@
-// SPDX-License-Identifier: Apache-2.0
-// Copyright (c) 2025 Matter Labs
+// SPDX-License-Identifier: BSD-3-Clause
 
 pub const NOTHING_TO_SEE_HERE: u8 = 0;