fix: update mypy config to support Python 3.9+ and ignore missing stubs

- Change python_version from 3.8 to 3.9 (mypy requirement)
- Add ignore_missing_imports to handle boto3/requests type stubs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: drernie

deploy/pyproject.toml

@@ -43,7 +43,9 @@ line-length = 100
 target-version = "py38"
 
 [tool.mypy]
-python_version = "3.8"
+python_version = "3.9"
 warn_return_any = true
 warn_unused_configs = true
 disallow_untyped_defs = true
+# Ignore missing type stubs
+ignore_missing_imports = true