Fix formatting issues: Standardize quotes to double quotes in __all__ list.

Author: 9chait9

src/google/adk/agents/__init__.py

@@ -53,16 +53,16 @@ def __getattr__(name: str):
         raise AttributeError(f"module {__name__} has no attribute {name}")
 
 __all__ = [
-    'Agent',
-    'BaseAgent',
-    'Context',
-    'InvocationContext',
-    'LiveRequest',
-    'LiveRequestQueue',
-    'LlmAgent',
-    'LoopAgent',
-    'McpInstructionProvider',
-    'ParallelAgent',
-    'RunConfig',
-    'SequentialAgent',
+    "Agent",
+    "BaseAgent",
+    "Context",
+    "InvocationContext",
+    "LiveRequest",
+    "LiveRequestQueue",
+    "LlmAgent",
+    "LoopAgent",
+    "McpInstructionProvider",
+    "ParallelAgent",
+    "RunConfig",
+    "SequentialAgent",
 ]