docs: Add link to CONTRIBUTING from README

Author: pierrepo

README.md

@@ -2,6 +2,8 @@
 
 Parquet files and codebook are available on Zenodo: [10.5281/zenodo.7856523](https://doi.org/10.5281/zenodo.7856523)
 
+see [CONTRIBUTING](CONTRIBUTING.md) if you want to contribute to this repo.
+
 ## Setup your environment
 
 Install [uv](https://docs.astral.sh/uv/getting-started/installation/).
@@ -12,12 +14,6 @@ Clone this repository:
 git clone https://github.com/MDverse/mdws.git
 ```
 
-> [!TIP]
-> For maintainers only:
-> ```bash
-> git clone git@github.com:MDverse/mdws.git
-> ```
-
 Move to the new directory:
 
 ```bash