Upgrade setup-uv action to v7

Bump astral-sh/setup-uv from v5 to v7 in the lint, spellcheck,
and type-check jobs.

This removes the Node.js 20 deprecation warning from GitHub Actions
for setup-uv and aligns the workflow with the Node 24 transition.

Author: kaste

.github/workflows/test-lint-go.yml

@@ -42,7 +42,7 @@ jobs:
         with:
           python-version: '3.13'
       - name: Setup uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v7
       - name: Install dependencies
         run: uv sync --frozen --group dev
       - name: Run flake8
@@ -58,7 +58,7 @@ jobs:
         with:
           python-version: '3.13'
       - name: Setup uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v7
       - name: Install dependencies
         run: uv sync --frozen --group dev
       - name: Run codespell
@@ -74,7 +74,7 @@ jobs:
         with:
           python-version: '3.13'
       - name: Setup uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v7
       - name: Install dependencies
         run: uv sync --frozen --group dev
       - name: Run mypy