fix dist make command

Author: thrau

Makefile

@@ -33,7 +33,8 @@ test-coverage: venv
 	$(VENV_RUN); coverage run --source=verdin -m pytest tests && coverage lcov -o .coverage.lcov
 
 dist: clean-dist
-	python3 -m build
+	python -m pip install build
+	python -m build
 
 install: venv
 	$(VENV_RUN); pip install -e ".[dev]"