dev env: add upper version constraint for isort to keep compatibility with python3.7 (has not reached end-of-life yet)

https://web.archive.org/web/20230203051620/https://github.com/PyCQA/isort/commit/47cedf3583f338e8ce9c906fc95c9fee6c57404d

https://github.com/fphammerle/python-manchester-code/commit/f174f7efcb41e22b7316211443752144e54205a0

Pipfile

@@ -15,6 +15,8 @@ pytest-cov = "*"
 # > File "[...]/python3.7/site-packages/_pytest/compat.py", line 56, in <module>
 # >  import importlib_metadata  # noqa: F401
 importlib-metadata = {markers = "python_version < '3.8'"}
+# https://github.com/PyCQA/isort/commit/47cedf3583f338e8ce9c906fc95c9fee6c57404d
+isort = "<5.12"
 # > File "[...]/python3.7/site-packages/importlib_metadata/__init__.py", line 6, in <module>
 # >  import zipp
 zipp = {markers = "python_version < '3.8'"}

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "385101f9ec2466f43e5158d6fcf2f25678ef5212511706e8f649e1717c6020fc"
+            "sha256": "bc1ca9e9ee2e9cea6424ebe37b95a9122b6eb8b0a5f25abe3b26909ab804978d"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -139,7 +139,7 @@
                 "sha256:6db30c5ded9815d813932c04c2f85a360bcdd35fed496f4d8f35495ef0a261b6",
                 "sha256:c033fd0edb91000a7f09527fe5c75321878f98322a77ddcc81adbd83724afb7b"
             ],
-            "markers": "python_version >= '3.7'",
+            "index": "pypi",
             "version": "==5.11.4"
         },
         "lazy-object-proxy": {