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](https://github.com/actions/checkout/compare/v2.3.2...a81bbbf8298c0fa03ea29cdc473d45769f953675)

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

.github/workflows/build.yml

@@ -27,7 +27,7 @@ jobs:
         shell: bash
 
       - name: Checkout the "hidden" branch
-        uses: actions/checkout@v2.3.2
+        uses: actions/checkout@v2.3.3
         with:
           ref: hidden