Add steps to install uv in venv

CONTRIBUTING.md

@@ -20,6 +20,14 @@ If you want to claim an issue to work on, you can write the word `take` as a com
     ```sh
     python -m venv .venv
     ```
+- Activate the created environment
+   ```sh
+    source .venv/bin/activate
+    ```
+- Install the [uv](https://github.com/astral-sh/uv) packet manager in the environment.
+  ```sh
+    pip install uv
+    ```
 
 - Build the project for development (this requires an active virtual environment and will also install `deltalake` in that virtual environment)
     ```sh