Bump actions/checkout from 3 to 4

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]>

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
             development: true
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - name: Install Erlang/OTP
@@ -86,7 +86,7 @@ jobs:
     steps:
       - name: Configure Git
         run: git config --global core.autocrlf input
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - name: Cache Erlang/OTP package
@@ -115,7 +115,7 @@ jobs:
     name: Check POSIX-compliant
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - name: Install Shellcheck

.github/workflows/notify.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-18.04
     name: Notify
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - uses: erlef/setup-beam@v1

.github/workflows/release.yml

@@ -41,7 +41,7 @@ jobs:
             build_docs: build_docs
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - uses: erlef/setup-beam@v1
@@ -67,7 +67,7 @@ jobs:
         run: |
           EX_DOC_LATEST_STABLE_VERSION=$(curl -s https://hex.pm/api/packages/ex_doc | jq --raw-output '.latest_stable_version')
           echo "EX_DOC_LATEST_STABLE_VERSION=${EX_DOC_LATEST_STABLE_VERSION}" >> $GITHUB_ENV
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         if: ${{ matrix.build_docs }}
         with:
           repository: elixir-lang/ex_doc