Bump actions/checkout from 3 to 4 (#101)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

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

.github/workflows/npm.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Actions checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup node
         uses: actions/setup-node@v3

.github/workflows/samples.yml

@@ -27,11 +27,11 @@ jobs:
           deno-version: v1.x
 
       - name: Checkout the api
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           path: ./deno-slack-api
       - name: Checkout the ${{ matrix.sample }} sample
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: ${{ matrix.sample }}
           path: ./sample