Bump actions/checkout from v2.3.0 to v2.3.1

Bumps [actions/checkout](https://github.com/actions/checkout) from v2.3.0 to v2.3.1.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/master/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.0...28c7f3d)

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

Author: dependabot[bot]

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out the repository
-        uses: actions/checkout@v2.3.0
+        uses: actions/checkout@v2.3.1
         with:
           fetch-depth: 2
 

.github/workflows/tests.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Check out the repository
-        uses: actions/checkout@v2.3.0
+        uses: actions/checkout@v2.3.1
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v2