Add type generation script

Author: kthota-g

development.md

@@ -0,0 +1,7 @@
+## Type generation from spec
+
+<!-- TODO replace spec.json with the public url so we always get the latest version-->
+
+```bash
+uv run datamodel-codegen --input ./spec.json --input-file-type jsonschema --output ./src/a2a/types.py --target-python-version 3.10 --output-model-type pydantic_v2.BaseModel --disable-timestamp --use-schema-description --use-union-operator --use-field-description --use-default --use-default-kwarg --use-one-literal-as-default --class-name A2A --use-standard-collections
+```