ci(deps): bump the github-actions group to major versions

Updates GitHub Actions to latest major versions:
- actions/checkout: v4 → v5  
- actions/setup-python: v5 → v6
- codecov/codecov-action: v4 → v5

All CI checks passed. Major version updates reviewed and approved.

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -19,10 +19,10 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
           cache: 'pip'
@@ -50,7 +50,7 @@ jobs:
 
       - name: Upload coverage to Codecov
         if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.12'
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           file: ./coverage.xml
           fail_ci_if_error: false
@@ -61,10 +61,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up Python 3.10
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.10"
 
@@ -85,10 +85,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        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: "3.12"
 

.github/workflows/dependabot-auto-merge.yml

@@ -16,7 +16,7 @@ jobs:
     if: github.actor == 'dependabot[bot]'
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Dependabot metadata
         id: metadata