fix makefile and instructions (#1569)

## Changes
fix makefile and update setup instructions

### Linked issues
None

### Functionality 

- [ ] added relevant user documentation
- [ ] added new CLI command
- [ ] modified existing command: `databricks labs ucx ...`
- [ ] added a new workflow
- [ ] modified existing workflow: `...`
- [ ] added a new table
- [ ] modified existing table: `...`

### Tests

- [x] manually tested
- [ ] added unit tests
- [ ] added integration tests
- [ ] verified on staging environment (screenshot attached)

Co-authored-by: Eric Vergnaud <[email protected]>

Author: ericvergnaud

CONTRIBUTING.md

@@ -227,7 +227,16 @@ def test_something(ws):
 
 This section provides a step-by-step guide to set up and start working on the project. These steps will help you set up your project environment and dependencies for efficient development.
 
-To begin, run `make dev` to install [Hatch](https://github.com/pypa/hatch), create the default environment and install development dependencies, assuming you've already cloned the github repo.
+To begin, install [Hatch](https://github.com/pypa/hatch), which is our build tool.
+
+On MacOSX, this is achieved using the following:
+```shell
+brew install hatch
+```
+
+The clone the github repo, and `cd` into it.
+
+To begin, run `make dev` to create the default environment and install development dependencies.
 
 ```shell
 make dev

Makefile

@@ -5,7 +5,6 @@ clean:
 	rm -fr **/*.pyc
 
 .venv/bin/python:
-	pip install hatch
 	hatch env create
 
 dev: .venv/bin/python