CI(deps): Update astral-sh/setup-uv action to v6.6.1 (OSGeo#6317)

Author: renovate[bot]

.github/workflows/additional_checks.yml

@@ -36,7 +36,7 @@ jobs:
         with:
           python-version: "3.13"
       - name: Install uv and restore its cache
-        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
+        uses: astral-sh/setup-uv@557e51de59eb14aaaba2ed9621916900a91d50c6 # v6.6.1
 
       - name: Check that files with the same content are the same
         run: |