Bump version to 2.11.3

[matthewcummings]

Summary

Bumps the version in pyproject.toml from 2.11.2 to 2.11.3 to prepare a patch release.

Context

The cryptography cap on the latest published release (v2.11.2) is ^46.0.0, which does not include the fix for CVE-2026-34180 (DoS via malformed ASN.1 input, patched in cryptography 48.0.1). Bots that depend on symphony-bdk-python cannot pin cryptography>=48.0.1 themselves because pip resolution fails against the transitive cap declared in BDK's own metadata.

The actual fix has already been merged to main via #390 — cryptography is now pinned to >=48.0.1,<49.0.0 and poetry.lock is regenerated accordingly. All that's missing to unblock downstream consumers is a published release cut from main.

This PR is just the version bump so that once merged, a maintainer can publish a GitHub Release tagged v2.11.3 and the existing release.yml workflow picks it up and pushes to PyPI.

Downstream impact

This unblocks CVE remediation on every downstream Symphony bot that depends on symphony-bdk-python — Symphony's InfoSec team is currently tracking the vulnerability across multiple bot deployments and the only unblock is a new release.

Test plan

• Verified pyproject.toml version field is the only change.
• After merge, a maintainer publishes a v2.11.3 GitHub Release from main.
• release.yml fires, poetry publish --build pushes symphony_bdk_python-2.11.3 to PyPI.
• Downstream bots pin symphony-bdk-python>=2.11.3 and verify pip install pulls cryptography 48.0.1.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: matthewcummings / name: Matthew Cummings (e757da8)