Add deprecation annotations

Author: shoumikhin

extension/apple/ExecuTorch/Exported/ExecuTorchModule.h

@@ -10,7 +10,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@available(*, message: "This API is experimental")
+__attribute__((deprecated("This API is experimental and may change without notice.")))
 NS_SWIFT_NAME(Module)
 @interface ExecuTorchModule : NSObject
 

extension/apple/ExecuTorch/Exported/ExecuTorchTensor.h

@@ -10,7 +10,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@available(*, message: "This API is experimental")
+__attribute__((deprecated("This API is experimental and may change without notice.")))
 NS_SWIFT_NAME(Tensor)
 @interface ExecuTorchTensor : NSObject
 

extension/apple/ExecuTorch/Exported/ExecuTorchValue.h

@@ -10,7 +10,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@available(*, message: "This API is experimental")
+__attribute__((deprecated("This API is experimental and may change without notice.")))
 NS_SWIFT_NAME(Value)
 @interface ExecuTorchValue : NSObject