Add deprecated decorator

Author: bruno-f-cruz

harp/__init__.py

@@ -1,5 +1,26 @@
 from harp.io import REFERENCE_EPOCH, MessageType, read
 from harp.reader import create_reader
 from harp.schema import read_schema
+import warnings
+import functools
+
 
 __all__ = ["REFERENCE_EPOCH", "MessageType", "read", "create_reader", "read_schema"]
+
+
+def deprecated(message):
+    # This decorator is only available from the stdlib warnings module in Python 3.13
+    # Making it available here for compatibility with older versions
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            warnings.warn(
+                f"Call to deprecated function {func.__name__}: {message}",
+                category=DeprecationWarning,
+                stacklevel=1,
+            )
+            return func(*args, **kwargs)
+
+        return wrapper
+
+    return decorator