Remove 'pip install' commands.

Author: anevolbap

Makefile

@@ -4,26 +4,21 @@ init:
 	python -m pip install -e .
 
 lint:
-	pip install causalpy[lint]
 	ruff check --fix .
 	ruff format .
 
 check_lint:
-	pip install causalpy[lint]
 	ruff check .
 	ruff format --diff --check .
 	nbqa black --check .
 	nbqa ruff .
 	interrogate .
 
 doctest:
-	pip install causalpy[test]
 	pytest --doctest-modules --ignore=causalpy/tests/ causalpy/
 
 test:
-	pip install causalpy[test]
 	pytest
 
 uml:
-	pip install pylint
 	pyreverse -o png causalpy --output-directory docs/source/_static --ignore tests