Update GitHub Actions to Node 24 compatible versions

Bump actions/checkout from v4 to v5 and actions/setup-python
from v5 to v6 across the CI workflow.

This addresses the runner deprecation warning for JavaScript
actions using Node.js 20 and prepares the workflow for the
Node.js 24 default.

Author: kaste

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

@@ -19,9 +19,9 @@ jobs:
           - '3.14'
     name: Run tests on Python ${{ matrix.python-version }} (${{ matrix.os }})
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Setup python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -31,14 +31,14 @@ jobs:
           pip install pytest numpy
       - name: Run pytest
         run: pytest
-        
+
   lint:
     runs-on: ubuntu-latest
     name: Lint with flake8
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Setup python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.13'
       - name: Setup uv
@@ -52,9 +52,9 @@ jobs:
     runs-on: ubuntu-latest
     name: Spellcheck with codespell
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Setup python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.13'
       - name: Setup uv
@@ -68,9 +68,9 @@ jobs:
     runs-on: ubuntu-latest
     name: Check with mypy
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Setup python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.13'
       - name: Setup uv
@@ -86,9 +86,9 @@ jobs:
     runs-on: ubuntu-latest
     name: Deploy to pypi
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.13'
     - name: Install dependencies