Bump actions/checkout from 2.4.0 to 3.0.2

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.4.0 to 3.0.2.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.4.0...v3.0.2)

---
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.yml

@@ -14,7 +14,7 @@ jobs:
     name: Flake8
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.4.0
+      - uses: actions/checkout@v3.0.2
       - name: Set Up Python
         uses: actions/[email protected]
         with:
@@ -34,7 +34,7 @@ jobs:
       matrix:
         python: [ '3.6', '3.7', '3.8', '3.9', '3.10' ]
     steps:
-      - uses: actions/checkout@v2.4.0
+      - uses: actions/checkout@v3.0.2
       - name: Setup Build Tools
         run: sudo apt-get install -y libkrb5-dev krb5-user krb5-kdc krb5-admin-server krb5-multidev
       - name: Set Up Python
@@ -58,7 +58,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v2.4.0
+        uses: actions/checkout@v3.0.2
         with:
           fetch-depth: 0
       - name: Set Up Python