build: remove isort

Import sorting now handled by ruff.

.pre-commit-config.yaml

@@ -12,12 +12,6 @@ repos:
     hooks:
       - id: black
         language_version: python3
-  - repo: https://github.com/pycqa/isort
-    rev: 5.13.1
-    hooks:
-      - id: isort
-        name: isort (cython)
-        types: [cython]
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: v0.1.7
     hooks:

CONTRIBUTING.md

@@ -82,7 +82,7 @@ The following steps are tested on an Ubuntu system.
     $ make test_all  # run all the tests, report all the errors
     ```
 
-9. Format your code. We use ```black``` for code and ```isort``` for ```import``` formatting.
+9. Format your code. We use ```black``` for code formatting.
 
     ```bash
     $ make style

Makefile

@@ -46,12 +46,10 @@ test_failed:  ## only run tests failed the last time.
 
 style:	## update code style.
 	black ${target_dirs}
-	isort ${target_dirs}
 
 lint:	## run linters.
 	ruff ${target_dirs}
 	black ${target_dirs} --check
-	isort ${target_dirs} --check-only
 
 system-deps:	## install linux system deps
 	sudo apt-get install -y libsndfile1-dev

pyproject.toml

@@ -64,8 +64,3 @@ max-returns = 7
 [tool.black]
 line-length = 120
 target-version = ['py39']
-
-[tool.isort]
-line_length = 120
-profile = "black"
-multi_line_output = 3

requirements.dev.txt

@@ -1,5 +1,4 @@
 black
 coverage
-isort
 nose2
 ruff==0.1.3