Update isort version in pre-commit config.

Setting up the pre-commit hooks fails due to a bug in isort (see:
PyCQA/isort#2083). This commit updates the
version to 5.12.0 where this bug was fixed.

Author: zoj613

.pre-commit-config.yaml

@@ -21,7 +21,7 @@ repos:
     hooks:
       - id: flake8
   - repo: https://github.com/pycqa/isort
-    rev: 5.10.1
+    rev: 5.12.0
     hooks:
       - id: isort
   - repo: https://github.com/pre-commit/mirrors-mypy