Bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci-checks.yaml

@@ -17,7 +17,7 @@ jobs:
         java-version: ['8']
       fail-fast: false 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v1
         with:
@@ -56,7 +56,7 @@ jobs:
         python-version: [3.7]
       fail-fast: false 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v1
         with:
@@ -77,7 +77,7 @@ jobs:
         python-version: [3.7]
       fail-fast: false 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v1
         with:

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

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ github.actor == 'dependabot[bot]' && github.event.workflow_run.conclusion == 'success' }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           ref: ${{ github.event.workflow_run.head_branch }}
       - name: Auto-approve Dependabot PR

.github/workflows/release-code.yml

@@ -13,7 +13,7 @@ jobs:
       max-parallel: 4
       fail-fast: false 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v1
         with: