gh-106978: Bump sphinx-lint to 0.6.8 (#106990)

Author: picnic-sven

.pre-commit-config.yaml

@@ -10,7 +10,7 @@ repos:
         types_or: [c, python, rst]
 
   - repo: https://github.com/sphinx-contrib/sphinx-lint
-    rev: v0.6.7
+    rev: v0.6.8
     hooks:
       - id: sphinx-lint
         args: [--enable=default-role]