Bump actions/checkout from 2.3.5 to 2.4.0 (#24)

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] <[email protected]>

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

.github/workflows/codecov.yml

@@ -5,7 +5,7 @@ jobs:
     name: codecov
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
       - uses: actions/setup-go@v2
         with:
           go-version: 1.14

.github/workflows/golangci-lint.yml

@@ -12,7 +12,7 @@ jobs:
     name: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
       - name: golangci-lint
         uses: golangci/[email protected]
         with:

.github/workflows/pre-release.yml

@@ -10,7 +10,7 @@ jobs:
   pre_release:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
         with:
           fetch-depth: 0
       - uses: actions/setup-go@v2

.github/workflows/release.yml

@@ -8,7 +8,7 @@ jobs:
   release:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.5
+      - uses: actions/checkout@v2.4.0
         with:
           fetch-depth: 0
       - uses: actions/setup-go@v2