chore(deps): update dependency isort to v6 (#13102)

* chore(deps): update dependency isort to v6

* Update compute/client_library/requirements.txt

---------

Co-authored-by: Katie McLaughlin <katie@glasnt.com>

Author: renovate-bot

compute/client_library/requirements.txt

@@ -1,5 +1,5 @@
-isort==5.13.2; python_version > "3.7"
-isort==5.11.5; python_version <= "3.7"
+isort==6.0.0; python_version > "3.9"
+isort==5.13.2; python_version <= "3.8"
 black==24.8.0; python_version < "3.9"
 black==24.10.0; python_version >= "3.9"
 google-cloud-compute==1.19.1