chore: Update .gitignore and add .python-version file

.gitignore

@@ -11,7 +11,6 @@ __pycache__/
 *~≈
 .env
 .envrc
-.python-version
 .idea
 .pytest_cache
 

.python-version

@@ -0,0 +1 @@
+3.12.4

rembg/bg.py

@@ -241,13 +241,13 @@ def remove(
     """
     if isinstance(data, bytes) or force_return_bytes:
         return_type = ReturnType.BYTES
-        img = Image.open(io.BytesIO(cast(bytes, data)))
+        img = cast(PILImage, Image.open(io.BytesIO(cast(bytes, data))))
     elif isinstance(data, PILImage):
         return_type = ReturnType.PILLOW
-        img = data
+        img = cast(PILImage, data)
     elif isinstance(data, np.ndarray):
         return_type = ReturnType.NDARRAY
-        img = Image.fromarray(data)
+        img = cast(PILImage, Image.fromarray(data))
     else:
         raise ValueError(
             "Input type {} is not supported. Try using force_return_bytes=True to force python bytes output".format(