github-actions(deps): bump actions/checkout from v2.3.2 to v2.3.3

Bumps [actions/checkout](https://github.com/actions/checkout) from v2.3.2 to v2.3.3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.2...a81bbbf)

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

Author: dependabot[bot]

.github/workflows/build.yaml

@@ -15,7 +15,7 @@ jobs:
                 php-versions: ['7.3', '7.4']
         steps:
             -   name: Checkout
-                uses: actions/checkout@v2.3.2
+                uses: actions/checkout@v2.3.3
             -   name: Setup PHP, with composer and extensions
                 uses: shivammathur/setup-php@v2
                 with: