fix: upgrade pip-tools to fix bug in version 6.6.1

This commit upgrades the version of pip-tools used in this repository from 6.6.1 to 6.6.2.

In version 6.6.1 of pip-tools, there is a bug that is preventing pip-tools from working. This is breaking the Python requirements update GitHub action in this repository.

The error is "AttributeError: 'RequirementSet' object has no attribute 'add_requirement'". The error was reported here: jazzband/pip-tools#1623. The fix to this bug was released in version 6.6.2 of pip-tools. See the pull request here: jazzband/pip-tools#1624.

requirements/pip-tools.txt

@@ -8,7 +8,7 @@ click==8.1.3
     # via pip-tools
 pep517==0.12.0
     # via pip-tools
-pip-tools==6.6.1
+pip-tools==6.6.2
     # via -r requirements/pip-tools.in
 tomli==2.0.1
     # via pep517