fix: Callback signer

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "c2pa-python"
-version = "0.11.1"
+version = "0.12.0"
 requires-python = ">=3.10"
 description = "Python bindings for the C2PA Content Authenticity Initiative (CAI) library"
 readme = { file = "README.md", content-type = "text/markdown" }

requirements-dev.txt

@@ -12,4 +12,7 @@ pytest-benchmark>=5.1.0
 requests>=2.0.0
 
 # Code formatting
-autopep8==2.0.4  # For automatic code formatting
+autopep8==2.0.4  # For automatic code formatting
+
+# Test dependencies (for callback signers)
+cryptography==45.0.4