Update ppl.cv.mdx

Author: nan2088

docs/backend-reference/ppl.cv.mdx

@@ -18,6 +18,7 @@ BUILD_PPLCV=1 pip install -e .
 | Name| Main Initialization Parameters |Runtime Parameters[Type] | Input[Type]  | Output[Type] | Note|
 | --- | --- | --- | --- | --- | --- |
 |[PPLResizeTensor]|resize_h,resize_w | resize_h[int],resize_w[int]|data[Tensor]|result[Tensor]||
+|[PPLResizePadTensor]|max_h,max_w | |data[Tensor]|result[Tensor]|Align to the top left|
 |[PPLWarpAffineTensor]|target_h,target_w|target_h[int],target_w[int],affine_matrix[vector\<float\>]|data[Tensor]|result[Tensor]|affine_matrix.size() == 6|
 |[PPLCopyMakeBorderTensor]||top[int],bottom[int],left[int],right[int]|data[Tensor]|result[Tensor]||