ci: sync lint.yml ruff pin to 0.16.3 (pin-sync contract)

Companion to the Dependabot pyproject bump: TestLintWorkflowPinSync
requires the lint workflow's installed versions to match the dev extra.
Verified locally: ruff 0.16.3 'ruff check diff_diff tests' is clean
(release changes touch bandit/pylint/pyupgrade/numpy rules, none in the
enabled E/F/I/W selectors).

Author: igerber

.github/workflows/lint.yml

@@ -39,7 +39,7 @@ jobs:
         with:
           python-version: '3.14'
       - name: Install pinned linters (keep in sync with pyproject [dev])
-        run: pip install ruff==0.16.2 black==26.5.1
+        run: pip install ruff==0.16.3 black==26.5.1
       - name: Ruff
         run: ruff check diff_diff tests
       - name: Black