Add minimal transformers version requirement

This metric depth estimation model will only be available with Release 4.45.0, and users need to install the latest version from the source or otherwise
cc

@qubvel-hf

README.md

@@ -39,6 +39,16 @@ alt="drawing" width="600"/>
 You can use the raw model for tasks like zero-shot depth estimation. See the [model hub](https://huggingface.co/models?search=depth-anything) to look for
 other versions on a task that interests you.
 
+### Requirements
+
+`transformers>=4.45.0` 
+
+Alternatively, use `transformers` latest version installed from the source:
+
+```
+pip install git+https://github.com/huggingface/transformers
+```
+
 ### How to use
 
 Here is how to use this model to perform zero-shot depth estimation: