chore: upgrade isort command

Author: Midnighter

Makefile

@@ -6,7 +6,7 @@
 
 ## Apply code quality assurance tools.
 qa:
-	isort --recursive src/structurizr/ tests/ examples/ setup.py
+	isort src/structurizr/ tests/ examples/ setup.py
 	black src/structurizr/ tests/ examples/ setup.py
 
 ## Prepare a release by generating the automatic code documentation.

tox.ini

@@ -21,9 +21,9 @@ commands =
 [testenv:isort]
 skip_install = True
 deps=
-    isort
+    isort >=5.0.5
 commands=
-    isort --check-only --diff --recursive {toxinidir}/src/structurizr {toxinidir}/tests {toxinidir}/setup.py
+    isort --check-only --diff {toxinidir}/src/structurizr {toxinidir}/tests {toxinidir}/setup.py
 
 [testenv:black]
 skip_install = True