chore(deps): update astral-sh/setup-uv action to v6

Author: renovate[bot]

.github/workflows/python-ci.yml

@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
 
       - name: Set up Python
         run: uv python install

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
 
       - name: Set up Python
         run: uv python install