Bump actions/checkout from 2 to 3.1.0 (#12)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.1.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3.1.0)

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

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

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

.github/workflows/on_pull_request.yml

@@ -28,7 +28,7 @@ jobs:
     name: Test - php:${{ matrix.php }}; composer:${{ matrix.composer }}
     steps:
       - name: Checkout
-        uses: actions/checkout@master
+        uses: actions/checkout@v3.1.0
       - name: Install PHP
         uses: shivammathur/setup-php@master
         with:

.github/workflows/update-wiki.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkouting main code...
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3.1.0
       - name: Updating Project Wiki...
         uses: impresscms-dev/[email protected]
         with: