fix(deps): raise the cryptography floor past PYSEC-2026-3552

embodied-action-receipts floored cryptography at >=42.0.8.
PYSEC-2026-3552 is a Bleichenbacher oracle: PKCS#7 EnvelopedData
decryption exposes distinguishable errors. Fixed in 50.0.0, which cmcp
already requires, so this brings the example in line with the runtime it
demonstrates rather than ahead of it.

A floor raise, not a pin. pip already resolves higher today; what this
removes is a resolution that could legally pick a vulnerable version in
an example whose subject is cryptographic receipts.

demos vendors this directory as a submodule, so it follows from here.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XbDBXDWWvMFa7c2jGgyq9t

Author: imran-siddique

embodied-action-receipts/requirements.txt

@@ -1,2 +1,2 @@
-cryptography>=42.0.8
+cryptography>=50.0.0