Fix README.md section about testing (conan-io#16326)

README.md

@@ -75,7 +75,7 @@ You can run Conan from source in Windows, MacOS, and Linux:
 Feedback and contribution are always welcome in this project.
 Please read our [contributing guide](https://github.com/conan-io/conan/blob/develop2/.github/CONTRIBUTING.md).
 Also, if you plan to contribute, please add some testing for your changes. You can read the [Conan
-tests guidelines section](https://github.com/conan-io/conan/blob/develop2/conans/test/README.md) for
+tests guidelines section](https://github.com/conan-io/conan/blob/develop2/test/README.md) for
 some advice on how to write tests for Conan.
 
 ### Running the tests
@@ -84,6 +84,7 @@ some advice on how to write tests for Conan.
 **Install Python requirements**
 
 ```bash
+$ python -m pip install -r conans/requirements.txt
 $ python -m pip install -r conans/requirements_server.txt
 $ python -m pip install -r conans/requirements_dev.txt
 ```