Bump actions/checkout from 2.3.5 to 2.4.0 (#22)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.5 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.5...v2.4.0)

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

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

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
           - os: macos-latest
             target: macos
     steps:
-    - uses: actions/checkout@v2.3.5
+    - uses: actions/checkout@v2.4.0
     - name: install apt packages
       if: ${{ matrix.os == 'ubuntu-latest' }}
       run: |
@@ -47,7 +47,7 @@ jobs:
       matrix:
         arch: [armv6, armv7, aarch64, ppc64le, s390x]
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
       - uses: uraimo/run-on-arch-action@v2.1.1
         id: build
         with:
@@ -84,7 +84,7 @@ jobs:
     if: startsWith(github.ref, 'refs/tags/')
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
       - name: generate changelog
         run: ./changelog.sh
       - uses: actions/download-artifact@v2