Add link in readme

Author: AntoinePrv

README.md

@@ -202,6 +202,8 @@ cmake . -DBUILD_TESTS=ON
 make xtest
 ```
 
+See also [CONTRIBUTING.md](CONTRIBUTING.md) for instruction to build and test automatically with Pixi.
+
 ## Building the HTML Documentation
 
 xsimd's documentation is built with three tools
@@ -230,6 +232,8 @@ make html
 
 from the `docs` subdirectory.
 
+See also [CONTRIBUTING.md](CONTRIBUTING.md) for a Pixi task to build the doc.
+
 ## License
 
 We use a shared copyright model that enables all contributors to maintain the