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

@@ -14,6 +14,9 @@ pylint-import-requirements = "*"
 pytest = "*"
 pytest-cov = "*"
 
+# python3.7 compatibility
+# https://github.com/PyCQA/isort/commit/47cedf3583f338e8ce9c906fc95c9fee6c57404d
+isort = "<5.12"
 # python3.10 compatibility
 # >   File "[...]/lib/python3.10/site-packages/mypy/main.py", line 11, in <module>
 # >     from typing_extensions import Final, NoReturn

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "9671951734ca75d0f441d9e6799a4dc7e659825c0a64ca9229291663b66477f2"
+            "sha256": "edcf9f0717c101f3fb7fe000d471022b5130cf97d8fcb5cb024f3effa2374c9d"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -166,7 +166,7 @@
                 "sha256:6db30c5ded9815d813932c04c2f85a360bcdd35fed496f4d8f35495ef0a261b6",
                 "sha256:c033fd0edb91000a7f09527fe5c75321878f98322a77ddcc81adbd83724afb7b"
             ],
-            "markers": "python_version >= '3.7'",
+            "index": "pypi",
             "version": "==5.11.4"
         },
         "lazy-object-proxy": {