[Tests] Add apps/official to lint environments

tox.ini

@@ -23,9 +23,9 @@ setenv =
 
 [testenv:lint]
 commands =
-    - poetry run black --check --diff biscuit/core/
-    - poetry run isort -c --diff --stdout -rc biscuit/core/
-    poetry run flake8 {posargs} biscuit/core/
+    - poetry run black --check --diff biscuit/ apps/official/
+    - poetry run isort -c --diff --stdout -rc biscuit/ apps/official/
+    poetry run flake8 {posargs} biscuit/ apps/official/
 
 [testenv:security]
 commands = poetry run safety check --full-report
@@ -39,8 +39,8 @@ commands = poetry run make -C docs/ html {posargs}
 
 [testenv:reformat]
 commands =
-    poetry run isort -rc biscuit/core/
-    poetry run black biscuit/core/
+    poetry run isort -rc biscuit/ apps/official/
+    poetry run black biscuit/ apps/official/
 
 [flake8]
 max_line_length = 100