Bump actions/checkout from v2.3.0 to v2.3.1 (#262)

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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.0
+        uses: actions/checkout@v2.3.1
 
       - name: Setup cache environment
         id: cache-env

.github/workflows/static.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v2.3.0"
+        uses: "actions/checkout@v2.3.1"
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"