makefile: Pin black version

Black keeps updating in the background and breaking our
CI due to slightly different formatting between versions.
Fix this by pinning the version.

Makefile

@@ -6,7 +6,7 @@ all: deps lint man package install
 
 # Install dependent pip packages, needed to lint or build
 deps:
-	$(PYTHON) -m pip install black isort pylint mypy build twine pytest pytest-mock
+	$(PYTHON) -m pip install black==24.1.1 isort pylint mypy build twine pytest pytest-mock
 	$(PYTHON) -m pip install .
 
 # Format using black