Bump actions/checkout from 2.4.0 to 3.5.3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.4.0 to 3.5.3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.4.0...v3.5.3)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checking out code from GitHub
-        uses: actions/checkout@v2.4.0
+        uses: actions/checkout@v3.5.3
       - name: Set up Python 3.8
         uses: actions/setup-python@v2.3.1
         with:
@@ -35,7 +35,7 @@ jobs:
         python: [3.7, 3.8]
     steps:
       - name: Checking out code from GitHub
-        uses: actions/checkout@v2.4.0
+        uses: actions/checkout@v3.5.3
       - name: Set up Python ${{ matrix.python }}
         uses: actions/setup-python@v2.3.1
         with:

.github/workflows/pythonpublish.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2.4.0
+      - uses: actions/checkout@v3.5.3
       - name: Set up Python
         uses: actions/setup-python@v2.3.1
         with: