Bump actions/checkout from 3 to 4 (#376)

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/main.yml

@@ -26,7 +26,7 @@ jobs:
       GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install OTP and Elixir
         uses: erlef/setup-beam@v1

.github/workflows/publish-to-hex.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout this repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install Erlang and Elixir
         uses: erlef/setup-beam@v1