Bump actions/checkout from v2.3.3 to v2.3.4

Bumps [actions/checkout](https://github.com/actions/checkout) from v2.3.3 to v2.3.4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.3...5a4ac90)

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

.github/workflows/build.yml

@@ -18,7 +18,7 @@ jobs:
         runs-on: ${{ matrix.operating-system }}
         steps:
             - name: Checkout
-              uses: actions/checkout@v2.3.3
+              uses: actions/checkout@v2.3.4
             - name: Setup PHP
               uses: shivammathur/setup-php@2.5.0
               with: