Fix Codebase __init__ typing for undefined programming_language (#184)

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Co-authored-by: codegen-bot <[email protected]>

Author: EdwardJXLi

src/codegen/sdk/core/codebase.py

@@ -129,7 +129,7 @@ def __init__(
         self,
         repo_path: str,
         *,
-        programming_language: ProgrammingLanguage,
+        programming_language: ProgrammingLanguage | None = None,
         projects: None = None,
         config: CodebaseConfig = DefaultConfig,
     ) -> None: ...